(3) potatoes and other fruits and vegetables; (4) meat of all kinds, fish and eggs; (5) milk and foods made from milk; (6) bread or cereal(谷类), rice is also in this kind of food; (7) butter, or something like butter.

　　People in different countries and different places of the world eat different kinds of things. Foods are cooked and eaten in many different kinds of ways. People in different countries eat at different times of the day. In some places people eat once or twice a day; in other countries people eat three or four times a day. Scientists say that none of the differences is really important. It doesn't matter whether foods are eaten raw(生的) or cooked, canned or frozen. It doesn't matter if a person eats dinner at 4 o'clock in the afternoon or at eleven o'clock at night. The important thing is what you eat every day.

　　There are two problems, then, in feeding the large number of people on earth. The first is to find some ways to feed the world's population so that no one is hungry. The second is to make sure that people everywhere have the right kinds of food to make them grow to be strong and healthy.

　　文章第一段叙述人们每天必需的七类食品；第二段说明了最重要的是吃的是什么；最后一段介绍了要解决的两个问题。

　　21. According to the scientists, which of the following groups of food is the healthiest for your lunch?

　　A. chicken, apples, cereal, cabbages

　　B. potatoes, carrots, rice, bread

　　C. oranges, bananas, fish, tomatoes

　　D. beef, pork, fish, milk

　　答案与解析：A　细节判断题。根据文章中科学家所提供的人们每天必需的七类食品，可知作中餐食品的 A 类最佳。

　　22. People in different countries and different places of the world ________.

　　A. has the right kinds of food to eat

　　B. cooks their food in the same way

　　C. has their meals at the same time

　　D. eat food in different ways

　　答案与解析：D　细节题。根据文章内容，不同的国家和地区，人们进食的方法也不一样。

　　23. If there is Paragraph 4, what do you think is going to be talked about?

　　A. When people eat their lunch.

　　B. What to do with the two problems.

　　C. How to cook food in different ways.

　　D. Why people eat different kinds of food.

　　答案与解析：B　推断题。在第三段里提到要解决的两个问题，如果有第四段，那么应该就是议论如何来解决这两个问题。

　　B

　　Randy Kraus was paralyzed(瘫痪的). His left side was useless. He'd been a police officer before, and he could do strong and able. Now, he felt he could do nothing.

His trouble started with Parkinson's disease, but it didn't end there. In July, 2002, the 60­year­old Kraus went into the hospital for an operation, on his brain to control the shaking. But he had a stroke(中风). He was paralyzed. The doctors said，"You