1. 根据句意和汉语提示写单词。

1. （1） Even the simplest everyday activities can  (减少) pollution.

3. （2） I think it is  (必要的)for us to master (掌握) a foreign language.

5. （3） My computer doesn't work. I have to get somebody to  (修理) it.

7. （4） We'd better take our own cloth bags instead of using  (塑料的) bags.

9. （5） Petrol(石油) is the most important  (产品) of many countries.