定语从句讲解：as的用法

　　"as"用法：

　　1)."as"引导限制性定语从句

　　a."such....as"

　　He is not such a fool as he looks.

　　I have never heard such a story as he tells.

　　b."the same ....as"

　　This is the same book as I lost last week.

　　(区分"the same...as"与"the same....that"：两者都引导定语从句。that从句中说明的名词与the same修饰的名词是同一个。as从句中说明的名词与the same修饰的名词是同一类，而非同一个。举例：①This is the same pen that I lost. 这支钢笔就是我丢的那一支。②This is the same pen as I lost. 这支钢笔跟我丢的那支笔一模一样。)

　　c."as...as"

　　As many children as came were given some cakes.

　　2)."as"引导非限制性定语从句

　　常用句式:as is said above 综上所述

　　as is known to all 众所周知

　　as is often the case 通常如此

　　as is reported in the newspaper 如报纸所报道的

　　6. “which”在特殊从定法

　　(1)不用that的情况

　　(a)在引导非限定性定语从句时。

　　(c)The tree, which is four hundred years old, is very famous here.

　　(b)介词后能用。

　　We depend on the land from which we get our food.

　　We depend on the land that/which we get our food from.

　　(2)只能用“that”引导：如先行词被“last,just”修饰时，只用“that”。

　　(d)先行词为序数词、数容词，又有人和物时。

　　(f)先行词指物，在主句中作是“the way”或“the reason”时，“that”可作关系副词，也可省略。

　　(h)主句的主语是疑问词“who /which”时，避免重复要用“that”.

　　举例：

　　Is this the book that you borrowed in the library?

　　这是你在图书馆借的书吗?

　　Who that break the window should be punished.

　　谁打碎了窗户谁该受罚。

　　All that needed is a supply of oil.

　　所需的是石油供应。

　　The thief gave out everything that he had stolen to the police.

　　那贼最终把偷的全部东西交给了警察。
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