1. 根据句意，选用方框内的词组填空。注意形式的变化。

make a difference, cut down, be good for, hear of, be harmful to

1. （1） The students  air pollution by walking to school last term.

3. （2） Your help has . I understand the work better now.

5. （3） All the people in the kingdom  the magic cloth before the king saw it.

7. （4） Pollution  our health. So we must protect our environment.

9. （5） "The food  you though it tastes awful," my mother said to me.