听力题 We have all heard about the importance of a balanced diet and seen poster after poster illustrating the four basic food groups and advising us to eat something from each group every day. Medical research has shown that the lack of a balanced diet can cause any number of physical problems, from fatigue to headaches to cancer. But if we take a wider view we realize that it is not the lack of a balanced diet that causes problems. A bad diet is the symptom of more deeply rooted social, cultural, and economic problems. When people don’t eat right, it is often because they can not afford to do so or because they have been so inundated with ads for fast food that they find convenience more attractive than good health. It may be because the stress of competing for success in school or at work has them seeking the comfort of candy bars, alcohol, and perhaps even drugs. Poverty, mass-marketing, and aggressive competition: these are the real causes of all the diet-related diseases. Putting posters of the four food groups in our classrooms will not begin to solve the real problems, which are too large to reduce to pictures on the wall.