The farmers are simply trying to fatten the animals in order to get a higher price on the market. Although some countries have tried to control such things, the practice continues.
文章大意：本文主要讲述的是食物可以让我们生存，但是现在的很多疾病也是与食物有关的。告诉我们要特别注意自己所吃的食物。
21．According to this passage, we can know ________.
A．perhaps most of human illness is caused by what we eat
B．perhaps most kinds of cancer are related to what people eat
C．cancer was discovered in 1945
D．science has made food unfit to eat
答案：A 细节理解题。根据第一段第三句话Some research has shown that perhaps 80% of human illness is related to food and 40% of cancer is related to food as well.可知，百分之八十的疾病都是由我们吃的食物引起的，故A项正确。
22．Things that are used to keep colours in meats are________.
A．harmful B．useless
C．helpless D．delicious
答案：A 细节理解题。根据第一段最后一句话In 1945, some researchers realized that things commonly used to keep colour in meats and other food additives(添加剂)caused cancer.可知，这些让肉着色的添加剂会导致癌症。那么对人体是有害的，故A项正确。
