1. I will never forget the ten years ___ we both spent in the little village.
A. when B. during which C. which D. in which
【答案】C。该题是定语从句。关系代词which在定语从句中做动词spent 的宾语。从句还原一下：we both spent ten years in the little village.
2. My vacation begins next Tuesday, ___ I will leave for Florida.
A. which B. that C. while D. when
【答案】D 从句意上可以判断该句后半部分是限定Tuesday 的定语从句，所以C项可以排除;在该定语从句中，先行词Tuesday在从句中作状语，应该是on Tuesday, 故引导定语从句可用on which或when。
3. Before joining the army, he spent a lot of time in the village ___ he belonged.
A. to which B. which C. to where D. at which
【答案】A。固定搭配belong to ：属于。因此选 to which。Where是连接副词不加介词。
5. The moon is a world that is completely still and utter silence prevails.
A. that B. where C. which D. whenever
【答案】B 这句话中world 带来两个定语从句，一是that is completely still“完全静止”，二是where utter silence prevails,“完全沉寂”，其中utter silence “完全的沉寂”，prevail v.“盛行，遍及”;这里必须用where 引导从句，是因为world 这个先行词在--utter silence prevails 中充当地点状语，where=in which,“在月球上';全句意为“月球是一个完全静止，完全沉寂的世界”。
6. The tsunami (海啸) ___ over 160,000 people were killed was a terrible disaster for human beings.
A. of that B. among which C. during that D. in which
【答案】D. 本题考查的是定语从句中关系词与介词的搭配使用。在海啸中丧生的搭配为dead in the tsunami, 因此应选D项，in which。
7. John isn't the same man before.
A. what he was B. that he was C. who he was D. as he was
【答案】D the same ....as...“跟....一样”， 是固定搭配。
8. We’ve tested three hundred types of boot, ____ completely waterproof.
A. no of which B. none of which C. some of that D. neither of which
【答案】B 可以判断该句为非限制性定语从句，而且引导词前有介词，指代物的引导词只能用which,而不能用 that。在这几个否定词中, none 表示对两个以上的事物的否定，neither 表示对两者的否定;它们都可以作代词，后面可以接单数，也可以接复数。no 不能作代词，不能在它的后面用介词。
9. ____ is well known, the key to success lies in hard work.
A. As B. That C. Which D. What
【答案】A.本题考查的是固定搭配as is well known，众所周知的意思。
10. He has made another wonderful discovery, ____ of great importance to science.
A. which I think it is B. of which I think it is C. I think which is D. which I think is
【答案】D 可判断句子为定语从句。有了which 指代discovery，就不应该再出现it;I think 作为插入语。
11.___ is known to all, too much smoking will cause lung cancer.
A. That B. It C. As D. What
【答案】C 固定用法as is known to all：众所周知。本句的意思是：“众所周知，吸烟过多会引起肺癌。B 用于it is known to all that…句型。
12.The investigation, ___ will soon be published, was made by John.
A. at which the results B. the results on which
C. whose results D. at whose results
【答案】C 此句考查非限制性定语从句。C选项正确,whose在从句中作定语;whose results=the results of which =the results of the investigation,定语从句修饰investigation;B选项中的on改成of就对了。
13. ______ is well-known, the environment in China is badly in need of improvement.
A. It B. That C. As D. What
【答案】C此题考查的是as 引导的特殊定语从句。As is well known/ as is known to all/ as we all know：众所周知。
14. They overcame all the difficulties and fulfilled the plan ten days ahead of schedule, ____ was something we had not expected.
A. that B. this C. it D. which
【答案】D 逗号后为非限制性定语从句，只能由which 或者who 引导，不能用 that。
15. ____ is well known, light, like heat, is a form of energy.
A. It B. What C. Just as D. As
【答案】D句意为：“如我们所知，光跟热能一样是一种能量的形式。”as is well known 为非限定性定语从句，修饰整个主句，意为“如我们所知”;as 代表整个主句“光跟热能一样是一种能量的形式。”