23. Having checked the doors were closed, and ______ all the lights were off, the boy opened the door to his bedroom. (2007湖南)
A. why B. that C. when D. where
[解析] B 所填选项引导宾语从句，从句中不缺任何成份和意义，只缺少连接词，所以用that引导。
22. It is none of your business other people think about you. Believe yourself. (2007 福建)
A. how B. what C. which D. when
[解析] B 该句中it作形式主语，what引导主语从句。该主语从句还原为疑问句应为“What do other people think about you?”。
21. Why not try your luck downtown, Bob? That’s ______ the best jobs are. (2007浙江)
A. where B. what C. when D. why
[解析] A That’s后为表语从句，此处where与downtown相呼应，根据句意可排除其他选项。
20. Choosing the right dictionary depends on ______ you want to use it for. (2007江苏)
A. what B. why C. how D. whether
[解析] A on后为宾语从句，此处用what引导宾语从句，在从句中充当介词for的宾语。
19. ______ he referred to in his article was unknown to the general reader. (2007上海)
A. That B. What C. Whether D. Where
[解析] B所填选项引导主语从句，且在从句中充当宾语，所以用what引导。
18. The seaside here draws a lot of tourists every summer. Warm sunshine and soft sands make ________ it is. (2007天津)
A. what B. which C. how D. where
[解析] A 此处用what引导宾语从句，在从句中充当表语。which引导宾语从句时意为“哪一个”，表示选择；how引导宾语从句时意为“如何”；where引导宾语从句时意为“在……地方”，均与句意不符。
17. He didn’t make ______ clear when and where the meeting would be held. (2007天津)
A. this B. that C. it D. these
[解析] C 此处用it作形式宾语，when and where the meeting would be held作真正的宾语。当复合宾语中的宾语是从句时，一般用先行代词it作形式宾语，而将从句放在补语的后面。
16. ____ matters most in learning English is enough practice. (2007全国II)
A. What B. Why C. Where D. Which
[解析] A所填选项引导主语从句，且在从句中充当主语，所以用what引导。
15. Could I speak to______ is in charge of International Sales, please? (2007山东)
A. anyone B. someone C. whoever D. no matter who
[解析] C to后为宾语从句，此处用whoever引导宾语从句，在从句中充当主语，此时whoever=anyone who；no matter who只能用于引导让步状语从句。
14. ______ we are sure about is the need to prevent children from being spoiled. (2008上海春招)
A. What B. Which C. Whether D. That
[解析] A 所填选项引导主语从句，且在从句中充当介词about的宾语，所以用what引导。
