【正文】 in a small town when I retire one day.Topic 14: Some people believe that university students should be required to attend classes. Others believe that going to classes should be optional for students. Which point of view do you agree with? Use specific reasons and details to explain your answer.Some people may believe that going to classes should be optional, but I disagree. I don’t understand how university students can expect to learn anything if they don’t attend classes. Personal experience can help people learn about themselves and the world outside the classroom, but when it es to learning about academic subjects, students need to be in class.In class they receive the benefit of the teacher’s knowledge. The best teachers can do more than just go over the material in the textbook. They draw their students into discussion on the material. They present opposing points of view. They schedule guest speakers to e, give the students additional information, or show documentary films one the subject.Also classes on any subject provide more than just facts. The students are taught how to learn, how to get information and then apply what they’ve learned in other situations. Their teacher is the best one to help them with these skills. They can’t learn them just by reading the textbook.By going to class, the students can learn how to work with the other members of the class. Many times, students will be given group assignments. This is different from what they did in secondary school. Here they are with people from different backgrounds and experiences. In this situation, they learn how to cooperate with people different from themselves to achieve a mon goal.In short, by going to class, students get more than just information from the teacher. They also learn how to learn, how to work with others, and how to work responsibly. These are not optional skills in life, so attending classes should not be optional.Topic 21: In general, people are living longer now. Discuss the causes of this phenomenon.People nowadays are living much longer than their counterparts in the past. In China, the average life expectancy has reportedly increased more that 4years since 1990. Among various factors that contribute to this phenomenon are the continuously advancing food condition, the rapidly developing medical care system, and finally the current stable social and economic circumstance.The food condition overall is being better and better, and is an important factor that makes people live much longer than before. First of all, foods are more hygienic. People today drink untainted mineral water, sterilized skim milk, which are cheaply supplied in supermarkets. Furthermore, foods are more nutritious, not to mention various carefully designed nutritious products. People can just ignore the possibility of being dystrophic, in that they can keep nutrients balanced by simply taking a cheap pill of vitamin pounds every day.Of equal importance is the rapidly developing national medical care system. Development of modern technology has always been amazing. Certain diseases such as tuberculosis, pneumonia, and dysentery are now easy to remedy with low expense, but in the past, they are all probably lethal. Dental technology seems developed little except its exorbitantly charged bill, yet the simplest technology contributes to people’s longevity most. It is not difficult to imagine that if an individual who lived in the past got a toothache, without certain dental care which is mon today, he was certainly in an awful prospect: he might even die of a toothache!Finally, the current stable economic circumstance is also a great influential factor. Social and economic circumstance has a dramatic effect on people’s life expectancy. It was reported that Russian life expectancy dropped from 70 to 58 shortly after the disintegration of the previous Soviet Union. Apparently, people have less pressure in a more stable society, and the less pressure they suffer, the healthier they are. At the same time, various types of insurance are readily available, which make people feel safe, and have to a large extent reduced people’ anxieties, therefore indirectly contributes significantly to longevity of people.補充：李笑來版本Among various factors that have made people live longer are the improvement of food condition, the development of modern medical technology, and the stability of social and economic environment. The improvement of food condition seems to be a very important factor. Compared to the past, much more assorted foods are available and at the same time more nutritious. Coarse food grain such as maize or sorghum had already been replaced by wheat flour and rice. Even the quality of drinking water has been improved. Water from river, water from well, and even tap water is no longer directly taken in。 what is now drunk is more likely to be mineral water, purified water, or distilled water. Besides, better nourishments are now cheaply available: a diverse array of vitamins can be supplemented by a single tiny pill. Equally important is the development of modern medical technology. Finer pharmacons and more effective treatments are continually developed and perfected, which means that many diseases for which there had been no previous effective treatment can now be easily cured. In the past, many pediatric diseases such as scarflet fever or whooping cough could cause an extremely high infant mortality. But now, such diseases are no Matching the improvement of food condition and the development of modern medical technology is another essential factor, the stability of social and economic environment. An obvious example is this: any war may well influence life expectancy of rival countries. On the contrary, in a relatively stable and secure environment, one is much more likely to be healthy. An insecure society can cause more stress, and under such stress, one is quite unlikely to be healthy