标签： 松江大学城快餐服务

　　Engine oil is the blood of the engine, which has the functions of lubrication, cooling, wear reduction, cleaning, sealing and rust prevention. A truly suitable engine oil for car engines can not only fully protect the engine, but also bring excellent driving experience and more economical fuel consumption performance.

　　How to choose the engine oil in the end? I believe many car owners don’t understand and are too lazy to think about it. When the car is being maintained, it will be handed over directly to the 4S shop. But is the engine oil in 4S shop really worth that much money? The more expensive the oil recommended by 4S shop, the better? After the warranty comes out in three to five years, will you still go to the 4S shop for maintenance?

　　Therefore, how to choose an engine oil that really suits your car should be what every car owner needs to know. If you want your car to stay with you for a longer time, you need 7 points for maintenance and 3 points for repair.

　　In this article, we introduce how to choose a really suitable engine oil from the perspective of popular science for engines with different car series, different displacements, different powers and even different car ages. When recommending more expensive engine oil in 4S shop, we have reason to refuse or indeed accept the engine better.

　　Many engine oil brands are marked with two important parameters in the most conspicuous place of the outer packaging: SAE engine oil viscosity standard and API engine oil grade standard. The former, such as 0W-40, 0W-30, 5W-40, 10W-60, etc., indicate the different viscosities of engine oil at low temperature and high temperature. The lower the number before "W", the better the low-temperature fluidity and the smoother the low-temperature cold start. The higher the number after "-",the higher the viscosity at high temperature, and the better the lubricity and sealing performance. At present, the widely used API grade of engine oil ranges from SL to SN PLUS, and the latest API grade has been developed to SP in 2020. From "SA" to "SP", with each increment of a letter, the performance of the engine oil will be better than the previous one, and there will be more additives in the engine oil to protect the engine. It can be clearly seen from the above table that the true meaning of oil viscosity.

　　0W is easy to understand. In the northern region where the temperature is very low, we can directly choose 0W or 5W engine oil, so we don’t have to worry too much. However, the kinematic viscosity of engine oil at 100℃ needs our careful choice. For most gasoline and diesel vehicles, when the engine water temperature reaches the normal 85-95℃, the engine oil temperature is in the range of 90-110℃, and it will not change greatly with the outside temperature. Therefore, the choice of 100℃ kinematic viscosity of engine oil only depends on the high-temperature viscosity requirements of engines of brand cars, regardless of the external environment temperature. To put it more bluntly, different engines should choose different engine oils with kinematic viscosity of 100℃, that is, the number after "-".

　　The higher this number, such as XW-405060′ s 100℃ high kinematic viscosity engine oil (hereinafter referred to as high viscosity engine oil), the greater the viscosity at high temperature, the thicker the oil film, the stronger the shear resistance, and the better the lubricity. The better the sealing between piston and cylinder wall, the better the dynamic response when driving at high speed. At the same time, it can also suppress the noise of the engine more effectively, but compared with waste oil. On the contrary, the smaller this number is, such as the 100℃ low kinematic viscosity engine oil of XW-3020168 (hereinafter referred to as "low viscosity engine oil"), it is easier to reach the normal working temperature at low temperature, and it is more fluid and fuel-efficient at high temperature. However, the oil film is easy to tear and lose its lubrication function when driving fiercely for a long time. A Japanese sports car owner used ordinary 20 low-viscosity engine oil to get off the track, which led to the engine size tile burning cylinder pulling to overhaul the engine. In addition, due to the relatively poor sealing performance of low-viscosity engine oil, the cylinder pressure couple releases pressure, which shows that when running at high speed, the engine speed rises but the speed does not rise, and the engine noise is relatively obvious. In order to solve these problems of low viscosity engine oil, it is often necessary to add more anti-wear and anti-wear additives, so the price is relatively expensive. This also reminds everyone that when choosing low viscosity engine oil, you must choose the engine oil of the regular big factory brand.

　　In addition, I have to say that the API standard can’t prove the quality of this oil. All oil manufacturers prepare their own oil according to API standards, and they can generally pass as long as they are willing to spend money to do bench tests in the United States. It’s like taking an exam. If you pass the exam with a score of 60 out of 100, you can get a "diploma". As long as it is not fake engine oil, engine oil meeting API SL, SM, SN, SN PLUS and SP levels will not cause damage to the engine, but it may not be suitable for your car. A really good engine oil, sometimes the API level is not high, let’s talk about it in detail below.

　　If the API standard in the United States is a passing line, then the ACEA standard in Europe is a good line with a score above 75. The European ACEA standard requires higher and more stringent quality of engine oil, which has stricter requirements for engine testing than API, such as adding a more stringent 150℃ HTHS high temperature shear test. Engine oil with API certification but no ACEA certification is not allowed to be sold in Europe.

　　For European cars, especially European turbocharged engines, there are strict requirements for the high temperature shear value of HTHS at 150℃, which needs to reach above 3.5. Different from the idea that Atkinson cycle and hybrid technology are widely used in Japan to improve the thermal efficiency, the European system prefers to use turbocharging to improve the thermal efficiency of the engine, which also passively improves the working temperature of the engine, so it requires higher HTHS values. The higher the HTSH value, the better the stability of the oil film at high temperature, and it is not easy to be torn, thus avoiding direct friction between metals (boundary friction).

　　ACEA contains the A/B/C/E standard, which represents the requirements of gasoline and diesel engines for engine oil. For most domestic gasoline engines, we only need to look at the A standard. As shown in the above figure, ACEA A3/B3, we only need to look at A3. The HTHS corresponding to A3 is above 3.5, which is suitable for most European turbocharged engines. Due to the increasingly stringent environmental protection requirements and the development trend of low viscosity engine oil, the highest A5 HTHS at present is between 2.9 and 3.5, and the SAE viscosity is roughly XW-20/30.

　　Write here and make a small summary. American API standards are universal. Just look at them, and don’t even use them as an important reference. If the API standard font on an oil bottle is particularly large and eye-catching, it means that it is hiding something. When choosing engine oil, you are advised to look at the European ACEA standard. The requirements of Japanese and American departments for HTHS are between 2.6 and 3.5, the corresponding ACEA standard is A5, the requirements of European departments for HTHS are above 3.5, and the corresponding AECA standard is A3.

　　If you want to know more about the ACEA 2016 standard, you can download the PDF document yourself:

　　https：//www.acea.be/news/article/acea-oil-sequences-2016-august-2018-update

　　However, remembering ACEA A5 and A3 is not enough.

　　ACEA engine oil standard has been very strict. If the engine oil that meets this standard can score 75 points, the engine oil that meets the engine oil standard issued by the main engine factory itself can get excellent results of more than 85 points. Therefore, oil manufacturers are actually very tired. They not only have to spend money to make API standards and sell them to most parts of the world, but also spend money to do ACEA tests and sell them to Europe. It will take more money and time if they want to get the certification from the OEM.

　　From the above picture, we can see three major certifications: European ACEA A3/B4; American API sn/sm; Main engine plants MB-Approval 229.5/229.3 (Mercedes-Benz certification), VW 502 00/505 00 (Volkswagen certification) and Porsche A40 (Porsche) certification. The engine oil certified by the main engine factory can be safely and boldly selected. Each OEM’s global official website has its own certified oil PDF document, which can be searched. The following one is from Mercedes-Benz:

　　https：//bevo.mercedes-benz.com/bevolistenmain.php？ navigation_path=bevolisten&language_id=0&blatt=229.5&content_action=show&mark=229.5&suchbegriff=229.5#close

　　So there are so many oils that meet the OEM certification, how should we choose? Read the instructions first! For example, the 2017 W213 Mercedes-Benz E-Class uses the M274 engine, and the instruction manual reads: Choose engine oil products that meet the MB229.5 standard. Under the premise of meeting this standard, we can choose different viscosity oils. For example, Mobil’s 0W-30 and 0W40 both meet this standard. If you want to save more fuel, you can choose 0W-30 engine oil, but low viscosity engine oil can’t suppress noise well, and the engine noise will increase. If you want quietness and dynamic response at high speed, you can choose 0W-40 engine oil, but you may use waste oil in your daily car. The main purpose of using the car is to travel in the city or to run long distances frequently. At this time, you need to think it over. For most family cars, I suggest that the thinner the SAE viscosity, the better, on the basis of meeting the engine oil standard.

　　In addition, many Volkswagen car owners asked if the oil products they bought were not certified by the public, but only the certification of Mercedes-Benz could be used. It can be definitely answered that except for super-running, the engine oil that meets the certification of Mercedes-Benz MB229.5 can be used in European cars, and the engine oil certification of Mercedes-Benz is the most stringent for European cars (except super-running). Why do you say that besides super-running? The engine speed of supercar or sports car is too high and the working environment is harsh. It is best to use the engine oil certified by supercar main engine factory. For example, Ferrari’s certified oil is Shell.

　　But I haven’t finished yet. The engine oil certified by the main engine factory can do the most comprehensive protection for the engine, but all-round development doesn’t mean all-round Excellence. We can also choose better engine oil according to our own demands for driving experience, quietness, fuel economy, cold start, and even playing off the track.

　　As mentioned at the beginning, API SN standard engine oil does not represent good engine oil. Because it can’t represent all the characteristics and parameters of engine oil, even if they are all called synthetic engine oil, their performances are very different with different base oils. Poly (α-olefin) synthetic oil (PAO for short) is produced into high-purity base oil by natural gas hydrogenation polymerization. It has good low-temperature fluidity and oxidation resistance, and is an ideal base oil for preparing high-grade and special lubricating oil.

　　However, the API grade of engine oil with high PAO content is not high. This is why, as mentioned at the beginning, API SN grade engine oil is not the best engine oil. For example, the domestic Mobil FS 0W-30 API is SL, and the top technology of Limo engine oil flagship product, 0W-30 API, is SM. In fact, API SN and SN PLUS grades mainly improve the requirements of environmental protection and low-speed early combustion of engine oil, and have little to do with lubricity.

　　Besides PAO base oil, there are Ester oil base oils. Ester base oils have excellent lubricity, especially whale ester, lard modified oil, etc., but their low-temperature fluidity is poor and they are easy to be oxidized. At the same time, in view of animal protection and cost, the current ester base oils are all artificially synthesized. Ester base oil can be used as an additive of PAO base oil to improve its lubrication performance. Pure ester oil, such as NUTEC in Japan, is a favorite product of many street car racing enthusiasts.

　　As we all know, there are mineral oil, semi-synthetic oil and fully synthetic oil, and the replacement mileage is 5000 km, 7500 km and 10000 km respectively, but the replacement mileage is not fixed according to different car scenes. If you often run high-speed, the whole synthetic engine oil can be extended to 15,000 kilometers for oil change. If there are frequent traffic jams or ethanol gasoline is used, it is best to change it every 8,500 kilometers in synthetic engine oil.

　　Why do you need to change the oil in advance when using ethanol gasoline? Let’s talk about the various parameters of engine oil. These parameters can be found on various engine oil brands official website, and even some conscientious Taobao and JD.COM online stores will post various parameters of engine oil for deep engine oil players to choose from.

　　Total base number (TBN)

　　The higher the total base number, the stronger the acid resistance of engine oil. Engines are made of metal, both aluminum and steel are alkaline in chemical elements, so they are afraid of acid corrosion. The higher the base number of engine oil, it can neutralize the acidic substances after gasoline combustion, especially ethanol gasoline.

　　40℃ viscosity

　　The lower the value, the easier it is for the engine to start.

　　100℃ viscosity

　　The higher the value, the thicker the oil film, better protection, better sealing, better noise suppression, but more waste oil. The lower the numerical value, the better the fluidity, the thinner the oil film, the relatively poor sealing performance, the relatively poor noise suppression and more fuel saving. Different engines have different requirements for 100℃ viscosity, too low will lead to the valve timing system can not be driven because of insufficient oil pressure.

　　pour point

　　The lowest temperature at which the oil can flow, the lower the value, the better, and the easier the cold start.

　　cloud point

　　At low temperature, the oil precipitates waxy turbidity, and the lower the temperature, the less turbidity the better, which proves that the PAO content of the oil is higher.

　　flash(ing) point

　　The higher the temperature at which the engine oil is ignited, the better. The higher the temperature, the less likely it is for the engine to knock. At the same time, the less oil is consumed (burning oil).

　　Evaporation loss

　　The smaller the evaporation loss, the less oil vapor and carbon deposition in the mixture.

　　Hths shear value at 150℃

　　Because of different models, there is no difference between good and bad. European cars generally require more than 3.5, while Japanese cars, American cars and Korean cars require more than 2.6. The higher the value, the more stable the high-temperature oil film and the better the lubrication performance.

　　The above table is the data of an original engine oil tested by Third International. When we choose engine oil, if we want to find an engine oil that is really suitable for car engines, the above parameter data needs to be well studied.

　　Speaking of which, I’ll make a summary of the first paragraph of the article. Is the oil recommended by 4S shop or repair shop really worth the price? You need to have a deeper understanding of engine oil to judge, and it has been made clear from what aspects you know about engine oil. For example, the ordinary engine oil in Mercedes-Benz 4S shop is fully synthetic.Yin Mobil no.1Or brand 5W-40 such as Petronas, it is no problem to maintain the car. But the AMG engine oil recommended by the store is fully synthetic.Jin Mobil 1 0W-40, various parameters are more biased.European version of Jin Mobil No.1Although the price is more than 300 yuan, it is really better for the engine, which is worthy of trust and money for purchase.

　　Finally, I collected some netizens’ oil problems as a summary of this article.

　　How to choose engine oil for different cars?

　　For Japanese cars, the engine work is precise, the tolerance value of thermal expansion and contraction is small, and the working temperature of Japanese engines is generally low, so it is basically recommended to use 0W-20 viscosity engine oil. In Japan, even 0W-8 engine oil has been used, which is as thin as water at room temperature. However, for some Japanese performance cars, it is recommended to use oil with higher viscosity. In addition, with the increasingly stringent global environmental protection requirements, low viscosity engine oil has become the future development trend. Mercedes-Benz’s latest MB229.71 oil standard can already use 0W-20 oil, but the engine meeting MB229.71 oil standard is still being tested.

　　American is Korean, and engine oil with viscosity of 0W-30 is basically selected.

　　At present, the majority of German engine oils are mainly 0W-40 engine oils and some 0W-30 engine oils with HTHS>3.5. In this respect, Audi has been at the forefront, and the specifications of some Audi models indicate that 0W-20 engine oil can be used.

　　Is 5W-40 an essential oil?

　　Yes. As long as it is real engine oil, 10W-60 mineral oil can’t break the engine, but choose a more suitable engine oil according to the car system. There is really no way. For example, if you run out of engine oil halfway and can’t find the right engine oil, you can use 5W-40 to temporarily solve the problem.

　　What kind of oil does the small displacement turbocharged engine choose?

　　Small displacement turbocharged engines are most prone to low-speed pre-combustion, that is, knocking. We should choose the engine oil that can inhibit low-speed pre-ignition, that is, API SN PLUS, and add gasoline that meets the label according to the requirements of the vehicle.

　　Power Magic stunt DX1 engine oil vapor can increase the ignition point of the mixture, thus reducing the knock probability.

　　What kind of oil do you choose for different car ages?

　　New cars can choose low-viscosity engine oil that meets the manufacturer’s certification or meets the manufacturer’s requirements for engine oil, that is, 100℃ viscosity and HTHS value. More fuel-efficient, but also more conducive to engine hot running.

　　The old car depends on the condition of the car. If the burning oil is obvious, try 10W-60 high viscosity engine oil. If there is no improvement, the engine can only be repaired.

　　Can different engine oil brands be mixed?

　　It is not recommended to mix different engine oil brands. Different additive formulations may lead to chemical reactions and reduce engine oil performance. Engine oils of the same brand can be mixed conservatively. For example, according to official confirmation of Mobil, different products of the same brand can be mixed. NUTEC grease engine oil in Japan even advocates consumers to buy oils with different viscosities and configure the required viscosities themselves.

　　How to distinguish between true and false engine oil, and what should I do if I buy fake engine oil?

　　Tmall, JD.COM official flagship store to buy engine oil, global purchase can buy imported engine oil, major engine oil manufacturers offline maintenance stores, there will be no fake. Personally, I prefer to buy imported engine oil online, but I must look at the reputation and evaluation of the store. The place where fake engine oil is most likely to appear is a small repair shop, so be careful. The above picture shows the European version of Jin Mobil No.1 FS 0W-40, with viscosity of 12.9 at 100℃ and HTHS 3.6 at 150℃, which is less viscous and more fuel-efficient than the engine oil provided by 4S shop, and has the certification of the main engine factory.

　　In case of buying fake engine oil, there will be obvious sludge on the dipstick, and black sludge can be seen at the engine oil port. At this time, change the oil quickly, replace the Burns oil with strong cleaning ability, drive for 1000 kilometers and then change it, and repeat it for 4 times to see the effect. Never add professional cleaning oil or cleaning products for the first oil change, it is easy to clean large pieces of sludge and block the oil passage, so that the engine can not be lubricated and the shaft is burned.

　　Can oil additives be added?

　　After the engine oil is finished, we will talk about the advantages and disadvantages of adding engine oil additives in the next article. Stay tuned.

　　For some small partners who have Xiaomi TVs at home, you can connect the TV to the Mijia app, so that you can control the TV in the Mijia APP, which is more convenient! So how can the Mijia APP add Xiaomi TV? The following small series has brought you a detailed tutorial. Interested small partners, let’s take a look!

　　1. Open the Mijia app on your mobile phone and click the "Add" option in the upper right corner.

　　2. In the Add Device interface of the jump, click the "Nearby Devices" option.

　　3. After that, the mobile phone will automatically start searching for nearby Xiaomi devices and wait for a while.

　　4. After completing the search, the Mijia app can automatically add Xiaomi TV.

　　The above is how to add Xiaomi TV to Mijia brought by the editor? Xiaomi TV tutorial has been added. For more related information tutorials, please pay attention to PConline.

Dear readers, welcome to stay tuned for updates from Mok. Today we will introduce you to a former kung fu superstar, an actor who rose to prominence in the golden age of Hong Kong cinema. He is Samuel Hung.

It is hard to believe that he once weighed more than 100 kilograms. However, a photo from 2020 is eye-popping. His face is clear-cut, and there is no fat on his neck. Only skin is left. This slimming mystery has attracted widespread attention.

But what is even more worrying is that in recent years, photos taken by netizens show that Hong Jinbao has had to rely on a wheelchair to go out.

This has sparked speculation about what made the former kung fu superstar so different. Some speculate that he may be sick, but what exactly does it take to make someone lose more than 25kg in just one year?

Mr. Hung was a shining star of the golden age of Hong Kong cinema in the 1980s. He helped bring Hong Kong cinema to its peak with kung fu stars such as Jackie Chan and Jet Li. His family background is also unusual. He was born into a film family. His grandfather Hong Ji and grandmother Qian Siying both left a strong mark on the history of Chinese cinema. This family background undoubtedly laid a solid foundation for Hong Jinbao’s acting career.

Hong Jinbao has been passionate about filming and kung fu since childhood. As a child, he entered the Peking Opera class of the China Academy of Drama to study. Among his classmates were many later kung fu superstars, such as Jackie Chan and Yuan Biao. And Hong Jinbao, as the oldest one, became the first person to set foot in the entertainment industry. At the age of 12, he entered the film industry as a child star. He began to participate in martial arts dramas at the age of 18. In his 20s, he has become a leading actor. Such achievements are no easy feat for a young person.

However, Samuel Hung’s career has not been smooth sailing. He once challenged Bruce Lee, but before he could stretch out his foot, Bruce Lee’s leg was already resting on his face.

The unexpected death of Bruce Lee scattered the martial artists who had followed him. For his own career, Hong Jinbao established the Hong Family Class. This group has trained many famous actors, including Jackie Chan, Afternoon Horse, Qian Jiale, etc. The most famous of them is Lin Zhengying. He became famous with "Mr. Zombie", and Hong Family Class also officially entered the Hong Kong film industry.

However, time is not forgiving. With the rise of the Internet, old-fashioned Hong Kong films have gradually been phased out by the times, and Hong Jinbao has gradually faded from the public eye. Although he directed and starred in a film "My Agent Grandpa" in 2016, his results are far worse than that of the year. He admits that he has not kept up with the changes of the times and feels like an old man who has been abandoned by the times.

In 2017, Samuel Hung underwent knee surgery. His knee problems have long been bothering him. After the surgery, the doctor advised him to lose about 25 kilograms of weight. Therefore, we have seen many photos of him on crutches or in a wheelchair in recent years. Samuel Hung follows the doctor’s advice very well. In general, he uses a wheelchair, and only in formal settings does he use crutches.

Photographs from 2020 show that Samuel Hung’s weight loss results are quite remarkable. He looks refreshed and in a good mood. However, in the past two years, he seems to have gained weight again. Some people have begun to wonder whether his illness caused the sharp weight loss. After all, a person’s sudden weight loss in a short period of time is often a sign of physical problems.

In fact, it was not out of the blue that Samuel Hung began to consciously control his weight after knee surgery. However, for the former kung fu superstar, his body has suffered too much damage, which may be the price of time.

Samuel Hung, a former screen star, is now old and away from the big screen. However, his classics will live on forever, and we hope he can take care of his body and have a wonderful time

Old age.

At this prime age, Samuel Hung may no longer be active in front of the screen, but his brilliance still illuminates the film industry. Countless audiences still miss his classic martial arts scenes and funny performances.

His works have long transcended the time of generations of audiences, becoming immortal classics that will forever remain in the pages of film history.

We cannot predict the future of Samuel Hung. Perhaps he will continue to be active in the entertainment industry in other ways, or he may choose to enjoy a peaceful retirement. Either way, his contributions and legends will always be remembered, and his story will continue to inspire a new generation of actors and audiences.

In the end, Samuel Hung’s experience tells us that time leaves its mark on everyone, but no matter what, we should cherish our health, fight against adversity, and embrace every stage of life. Samuel Hung was the "flexible fat man", and now he is the eternal kung fu superstar in our hearts.

Responsible editor:

　　Bright pictures/vision china

　　[thoughts]

　　editorial comment/note

　　Labor refers to the activity that people create material wealth and spiritual wealth necessary for their own survival and development through their own hard physical or mental efforts. In the new era, labor education has been picked up again, and schools have gradually begun to jointly carry out labor education practice with society and families. But in reality, labor education is often reduced to a simple task in daily teaching, a simple physical education, skill learning, and even alienated into entertainment, punishment and domestication. This paper holds that the lack of understanding of the connotation of labor and labor education still leads to some misunderstandings in the practice of labor education, such as the "servitude" of cognitive mental work that makes learning and labor oppose each other, the "play" that replaces the real pleasure of labor, and the lack of continuity in labor education, which needs serious reflection based on the connotation of labor education, and has certain practical pertinence, hoping to bring inspiration to readers.

　　1, learning "servitude" put learning and labor in opposition.

　　In recent years, labor education has been promoted to the same position as moral education, intellectual education, physical education and aesthetic education, so some schools have vigorously carried out labor education practice. Some open up schools to build farms and guide students to carry out productive labor practice; Some combine social resources and rely on labor education practice bases to organize students to experience labor. Social practice activities of learning agriculture and learning industry are carried out regularly every year in many places. However, while increasing the opportunities of labor experience, we will find a conventional concept that students’ daily study is not labor. This is really worth reflecting on. Isn’t learning itself labor?

　　In fact, learning itself is also a kind of labor, and learning is cognitive mental labor. Soviet educator Suhomlinski believes that "labor education begins when students sit behind desks and study. Desk is the most complicated machine tool, which makes children, teenagers and teenagers feel that it is shameful to be careless, and laziness and idleness are sad. It is the most difficult thing for students to establish this understanding in education". Learning is a kind of labor that promotes the combination of wisdom and hands’ efforts. In this labor, learning is labor, while knowledge is the result of labor efforts. Under the background of digital labor era, the function of labor gradually turns to the existential function of realizing personal self-worth and obtaining the sense of value and meaning of existence. From this perspective, completing labor outside of learning may not be able to obtain more sense of value and existence than learning process.

　　If learning is labor, why talk about labor education now? Why didn’t the mental work, which occupies the main position in students’ life at present, achieve the purpose of labor education? Why do schools often oppose mental labor and productive labor, and think that too much emphasis on intellectual development leads to insufficient labor experience? This is because the mental work of learning is alienated, and learning has been externalized as "labor".

　　To recognize that learning is externalized as "labor", we need to trace back the essence of learning, a mental labor, and re-examine the current learning process of students. From Marx’s definition of labor, we can see that labor is first of all a process between man and nature. In the process of material exchange with nature, man is increasingly aware of the common attributes of things and phenomena, and finds the regularity and connection between them, while mental labor is expressed in the form of representation, concept and reasoning. Learning this mental work ultimately points to scientific understanding of things, which is also an essential attribute for learning to become mental work. At present, students’ learning has gradually become "externalized labor" pointed out by Marx. Marx said in the Manuscript of Economics and Philosophy in 1844: Labor is an external thing for workers. In labor, he does not affirm himself, but denies himself. Instead of feeling happy, he feels unfortunate. Instead of freely exerting his physical strength and intelligence, he tortures himself physically and mentally. Once the external force stops, he will escape from labor like a plague. This exposition of externalization of labor seems to be just right to describe the study of today’s students. Students’ study is not to scientifically understand reality, but to pursue external material needs. The "tearing books after the college entrance examination" repeatedly exposed by the media reflects the students’ escape from this externally imposed task. Therefore, learning is no longer real labor, and it no longer has the function of liberating physical strength and intelligence.Instead, it becomes "hard labor", so it has little effect on improving students’ labor literacy.

　　2. "Gamification" makes students lose their interest in labor.

　　Corresponding to the fact that learning has become "hard labor", other forms of labor education that are gradually emerging show a trend of "gamification". Some schools carry out interesting and wonderful labor activities to attract students, and some schools integrate labor education into spring outing. On the one hand, this can improve students’ enthusiasm for participating in labor, but on the other hand, we need to pay attention to avoid blurring the difference between labor and games. Labor is the process of externalizing oneself, while game is the process of internalizing reality. The fuzziness of the difference between labor and games is more obvious in the digital age. Digital labor blurs the time-space boundary between entertainment and work, and dispels the traditional antagonistic relationship between play and labor.

　　Labor is a serious process of giving, and the joy of labor lies in creation. This kind of giving also explains the self-externalization of labor. Students devote their physical strength and intelligence to the labor process and gain certain results. The pleasure that students feel in their work is the pleasure of creating things because of self-sacrifice, not fun. There is a difference between labor and games. Games can naturally bring satisfaction to children, but labor itself has no interest in children, so the interest in labor needs to be cultivated and developed consciously. The gamification of labor makes many activities look interesting, but there is no labor in essence, and students can’t gain interest in labor. Suhomlinski believes that the interest in labor should be manifested as "they realize that they can act on nature, make plants give fruits, and use tools to process wood or metal into needed shapes". Therefore, in the practice of labor education, we need to judge whether the interest in the labor process comes from giving and creating, or is interfered by other factors such as gamification.

　　The contribution in the process of labor can cultivate positive labor values and make students love the working people and respect the fruits of labor. At the end of the 19th century, a "new" school appeared in France to train people engaged in "advanced knowledge occupations". In this school, students treat manual labor just like games and sports, because they don’t have to live by manual labor in the future. Although this school is located in the countryside, the students are far away from farmers’ lives. Although they are also working, they can’t really understand and study various social relations. Rousseau believes that only by taking part in labor in person and understanding all its complexity and arduousness according to experience can students judge the social significance of a production department in the future. Therefore, if we don’t regard labor as a serious process, we can’t cultivate our feelings for the working people, and we can’t cultivate our appreciation for the obtained survival materials.

　　3. Labor education stays in experience and ignores daily self-service labor.

　　At present, the labor practice of studying industry and agriculture in some areas is vigorously carried out, and an institutionalized labor experience system is gradually formed based on the construction of learning industry and agriculture bases. However, the persistence of these activities is worthy of attention. Most schools spend one week each semester leading students to experience labor, but they only stay in the experience once each semester, and there is a lack of cohesion between the activities, which is easy to make the labor experience become a casual entertainment. What’s more, some schools organize students to pull weeds in wasteland, and students regard pulling weeds as a kind of hard labor. This kind of labor experience of "working without teaching" deepens students’ rejection of manual labor. Therefore, the experience of labor must be complete, so that students can see the results of labor and feel satisfied with the achievements they have made through their own labor. If we just stop at pulling weeds without letting students experience the significance of pulling weeds for the growth of saplings, it will be difficult for this labor experience to play its due role. To lead students to plant wheat seedlings, we should let them see the process of wheat seedlings growing, heading and harvesting, and even let them see the process of wheat grains turning into food. At this time, the sense of pleasure comes not only from obtaining external products, but also from experiencing the sense of value and existence of labor.

　　In fact, daily self-service labor is just the way to implement the principle of continuity of labor education. However, these are often ignored in schools and families. Schools spend time and energy to organize off-campus labor practice, but at noon, catering staff bring students lunch to the classroom, "depriving" students of the opportunity to experience self-service. The relationship between man and self is at the core of the three attributes of man, which also means that students’ self-service labor plays a vital role in students’ all-round development. Self-service labor can be regarded as the beginning of labor education. No matter what kind of productive labor he is engaged in in in the future, self-service will become his obligation and habit, and it is also the habit of cultivating people to observe discipline, meet their personal needs by doing it themselves, and form the habit of respecting others. When students get food effortlessly, it is difficult to ask them to respect food and labor.

　　4. Strategies and suggestions for getting out of the misunderstanding of labor education practice.

　　"If there is labor, there may not be education". Labor needs to satisfy three relational attributes, namely, man and self, man and nature, and man and society. The basic contents of labor are: self-service labor, productive labor and social welfare labor. Labor education is a practical activity based on physical labor and material production labor, exploratory innovation labor and artistic aesthetic labor, which is manifested in independent life in family life, practice and hands-on operation in study, public welfare activities in society and various professional labor. Therefore, the strategy to get out of the misunderstanding of labor education practice is to balance people’s different forms of labor demand through diversification.

　　First of all, set up a cohesive and comprehensive labor education course. Dewey once said in The Waste of Education that all aspects and stages of education lack the necessary connection and cohesion with each other, which leads to conflicts and even negative effects. Similarly, in order to avoid the waste of education caused by labor education staying at the experience level, the labor education curriculum needs to pay attention to the cohesion of labor content and skills, which is reflected in the cohesion of curriculum content and the cohesion of education system. In terms of course content, it is necessary to set up labor courses that echo and connect properly according to the needs and characteristics of students of different classes and grades. In the education system, it is necessary to consolidate the skills and concepts of labor education through the cooperation between family and society. Schools can encourage students to find service jobs at home, take the initiative to participate in housework, and learn some labor skills. In addition, the content of labor curriculum also needs to take into account three basic labor education contents, namely, self-service labor, productive labor and social welfare labor.

　　Secondly, change the concept of labor education of parents and educators, so that parents and educators can establish labor education awareness. The promotion of the cooperative mechanism between labor educators and schools puts forward higher requirements for teachers and parents’ awareness of labor education. For example, some schools will arrange "homework". If teachers and parents can’t pay attention to it, the effect will be greatly reduced. In order to avoid staying in the curriculum, labor education needs to enhance the awareness of teachers and parents. On the one hand, it is necessary to interpret the connotation, function and significance of labor education in combination with the development of the new era. On the other hand, it is necessary to change the concept of labor education through necessary education and training, so that they can voluntarily carry out and cooperate with the development of labor education activities.

　　Finally, actively develop creative forms of labor and promote the combination of physical strength and brain power. Creative labor enables students to use the power of wisdom in physical labor, realize the unity of "internal thinking" and "external doing", and thus experience the happiness of labor. Wang Shaoliang, a scholar, believes that the labor values of contemporary teenagers have changed from "labor glory" to "labor happiness", that is, from "a kind of praise obtained from the outside through labor achievements" to "confirmation and affirmation of an essential force from their own labor achievements". Therefore, the development of school labor activities can not stay in simple physical labor, but needs to develop challenging creative labor that can show students’ physical and mental potential. Suhomlinski’s "creative labor theory" also points out that the content of labor education should be enriched with enough knowledge, abundant wisdom and refined talents.

　　 (Author: Ning Bentao Feng Linlin, respectively, professor of the Department of Education, Department of Education, East China Normal University, researcher of the Institute of Basic Education Reform and Development; Master student, Department of Education, East China Normal University)