11. People can protect the environment by ___________.

10. Rubbish must be s_________ into different bins and then recycled.

C. 根据句意，用括号内所给单词的适当形式填空。

　　 wise; harm; different; recycle; punish

9. The Maths problem is s__________, but I don’t think every student can work it out.

8. The write d__________ on his pen for a living.

7. All l__________ things need food and water to survive.

6. —What’s in the big red box? —Nothing. It’s e__________.

5. Does this new energy __________ (产生) pollution？

B．根据句意及首字母提示完成单词。

4. They are doing a __________(调查) these days.

3. Do your parents __________ (允许) you to come home late after school?

2. The government still face very ___________ (严重的) difficulty.