12.答案:D

解析:who引导宾语从句,要用陈述句的语序.所谈到的人不清楚是男是女时,要用it来指代.

11.答案:A

解析:主语从句she couldn't understand缺少宾语,要用What引导.表语从句fewer and fewer students showed interest in her lessons是一个完整的句子,要用why引导.

10.答案:D

解析:这是宾语从句.宾语从句中he had done后缺少宾语,要填what.

9.答案:D

解析:宾语从句中it was后缺少表语.in some book or another表明这里指的是哪本书,要填which.

8.答案:B

解析:that引导同位语从句,作information的同位语,解释information的具体内容.

7.答案:C

解析:这是宾语从句.宾语从句中to do后缺少宾语,要填空what.

6.答案:A

解析:这是宾语从句,wants后面缺少宾语,要填写what.Always give the monkey exactly what he wants是一句谚语,意思是"永远给与某人他确实想要的东西".

5.答案:B

解析:这是主语从句.主语从句是一个完整的句子,要填That.

4.答案:C

解析:这是宾语从句,宾语从句中we can do后缺少宾语,要用what填写.

3.答案:A

解析:what在表语从句中作takes的宾语,构成"It takes sth.to do sth."的句型.