5. D

they thought 为插入语，可以去掉，则就可以看出宾语从句中缺少主语。whoever=anyone who。故选D。

4. B

主语从句____made things worse 缺少主语，应用what引导。that在名词性从句中连接词的作用，不充当任何成份。故选B。

3. B

at what time=when，引导宾语从句，when在从句中充当时间状语。故选B。

2. B

　when引导表语从句，表示时间。故选B。

1．A

本题含有强调句型，若把It is···that去掉，则很容易地看出what引导的宾语从句，what在从句中充当主语。故选A。

40.　 ______ he met with the difficulty did he realize the importance of our help.

　 A. Even though　　　 B. Never until　　　 C. Only before　　　 D. Ever since

[答案与解析]

39. The women carrying babies , come in first ,　　　 　?

　　 A．will you 　　　　　　　 B．will they 　　　　　　 C．do you 　　　　　　　 D．don’t you

38．In no country other than Britain, it has been said, ____ experience four seasons in the 　course of a single day.

A. people can　　　　　 B. you can　　　 C. can it　　　　　　　　　　 D. can one

37. They have no idea at all ____.

A. what he is working on　　　　　　 B. what is he working on

C. what did he work on　　　　　　 D. what he is working

36. 　　　　on the top of the mountain is an ancient tower dating back to hundreds of years ago .

　　　 A．To stand 　　　　　　 B．Having stood 　　 C．Standing 　　　　　　 D．Stand