5. 选T。从短文的最后一句To keep the balance of nature is important for us to remember. 我们知道：保持生态平衡对我们来说是非常重要的。

4. 选F。由短文内容可知，如果人们不破坏生态平衡，而顺其自然，则动物的数量不会有多大的改变。故本题与原文不一致，所以判断此题错误。

3. 选T。由句子If the animals can’t find enough plants to eat, they will starve or have to leave the place. 可知本题正确。

2. 选F。本题句意为“田鼠不仅吃小鸡还吃农民的庄稼”，但由句子Field mice were eating up a lot of the farmers’ grain. 可知，田鼠只吃庄稼，

1. 选T。根据句子 “Kill the hawks,” the officials said. 可知，此题与短文内容相符合，所以可判断为正确。

5. It is important for us to keep the balance of nature.

[答案及解析]

4. The number of animals changes much if people leave things as they are.

3. When the animals can’t find enough plants to eat in a place, they will starve or have to leave.

2. Field mice eat not only chickens but also the farmers’ grain.

1. Finally the officials told the farmers to kill the hawks.