A
Paragraph 1: Scientists have learned a lot about the kinds of foods people need. They say that there are several kinds of foods that people should eat every day. They are:（1）green and yellow vegetables of all kinds;（2）citrus（柑橘）fruits and tomatoes;（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（谷类食物）, rice is also in this kind of food;（7）butter, or something like butter.
Paragraph 2: People in 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 or cooked. It doesn't matter if a person eats dinner at 4 o'clock in theafternoon or at eleven o'clock at night. The important thing is what you eat every day.
Paragraph 3: There are two problems, then,in feeding the large number of people in the 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 foods to make them grow to be strong and healthy.