1.___ is known to all, too much smoking will cause lung cancer.

　　A. That B. It C. As D. What

　　C 固定使用方法as is known to all：大家都知道。本句的意思是：大家都知道，抽烟过多会引起肺癌。B 用于it is known to all that句型。

　　2.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

　　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。

　　3. ______ is well-known, the environment in China is badly in need of improvement.

　　A. It B. That C. As D. What

　　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：大家都知道。

　　4. 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

　　D 逗号后为非限制性定语从句，只能由which 或者who 引导，不可以用 that。

　　5. ____ is well known, light, like heat, is a form of energy.

　　A. It B. What C. Just as D. As

　　D句意为：如大家所知，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，意为如大家所知;as 代表整个主句光跟热能一样是一种能量的形式。

　　6. The day breaks ________the birds are singing.

　　A. in that B. which C. on that D. in which

　　A 天亮了由于鸟儿在歌唱。in that 由于。

　　7. Liquids are like solids ______ they have a definite volume.

　　A. in that B. for that C. with that D. at that

　　A 液体像固体一样有确定的体积。in that 由于。

　　8. Criticism and self-criticism is necessary _____ it helps us to find and correct our mistakes.

　　A. by that B. on that C. on that D. in that

　　D 批评和自我批评非常重要由于他帮助大家找出和纠正大家的错误。in that 由于。

　　9. Britains press is unusual ________ it is divided into two very different types of newspaper：the quality press and the popular press.

　　A. in how B. in what C. in which D. in that

　　D 英国出版社不同于普通出版社，它被分为两种不同类型的报纸，优质的报纸和时尚报纸。in that 由于。

　　10. The high income tax is harmful ______ it may discourage people from trying to earn more.

　　A. in that B. in which C. that D. which

　　A 高税收有害，由于他或许会挫伤大家试图挣更多钱的积极性。in that 由于。