7. 专家建议我们立刻采取行动与空气污染作斗争。(advise, fight)

6. 她假装病了，请了一天假。(pretend)

5. 一旦被加热，琥珀可以被制成各种形状。(连词+分词结构)

4. 她给了我们食物和衣服，没要求任何回报。(in return)

3. 我拿不准这礼物是谁的。(belong to)

2. 他不可能把书带回家，因为他所有的书都在桌子上放着呢。(情态动词+have done)

1. 毫无疑问，他将为他所做的受到处罚。(doubt)

10. He ____________(pretend) to be doing his homework when he saw his mother come in.

9. Only women and children _____________(remain) in the village when the men went out to work.

8. Who can ____________(prove) that China has more people than any other country in the world?