1、、 。 as 与 which 引导非限制性定语从句的区别as 的特殊用法1、如果要说明两者有相似之处时通常用 as，表达“正如（情形或事实所表示）的那样、像的一样”的意思。例如： She is a fine singer，as her mother used to be她是一个很出色的歌唱家，和她母亲当年一样。 She is the same age as you (are). 她和你年龄一样大。与 same.as 连用I hope to get such a dictionary as he is using. 我希望有一本和你正在用的一样的词典。 与 such.as 连用 As water
2、 is to fish, so air is to man. 正如水对鱼一样重要，空气对于人同样重要。She has married again，as was/seemed natural她又结婚了，这很自然。 2、as 常与从句中的 know，see ， hear，expect 等动词连用，也常用于 as often happens，as is often the case（常有的事）等句子中。As you know, he is from Beijing. 正如你所知道的，他来自北京。As is known to everybody，the moon travels round the e
3、arth once every monthHe was absent，as is often the caseAs you will find out, all is now settled. 你将会看到这样的情况，一切都已搞定了。3、as 引导的非限制性定语从句的位置比较灵活，既可位于所修饰的句子之后，也可位于句中或句首；而由 which 引导的非限制性定语从句一般不位于句首。例如： As you will find out，I will never let you down你将会发现，我绝不会使你失望的。 4、as 所引导的从句所表达的语意须和主句一致，表示在预料之内的 ，就用 as,而
4、which 则用于表示在预料之外的情况，或突发性的事情。例如： She has married again，which was unexpected她又结婚了，真不可思议。（此处不可用 as）5. The burst of the gas pipes happened the other day, which shocked all of us.这类定语从句只能由 which 或 as 引导。两者之间的区别在于：1. which 引导的定语从句只能位于主句后，但 as 引导的从句可位于主句前、中、后。如：David, as you know, is a photograopher. 戴维是个摄
5、影师，你是知道的。(不可用 which)Li Ming is late, as is often the case. 李明迟到了，这事是经常发生的。(不可用which)2. as 在定语从句中作主语时，从句谓语通常要有 be 或别的系动词，但 which 不受此限制。如：Li Ming was late, which (=and this) made Mr. Zhang very angry. 李明迟到了，这件事使张先生非常生气。(不可用 as)3. as 引导的定语从句只表示一个众所周知或意料之中的事，但 which 不受此限制。如：He married her, which was une
6、xpected. 他和她结婚了，这是出乎意料的。( 不可用 as)4. as 有“正如”之意，而 which 则意为“这( 件事，一点 )”，可用 and this/that/it 来代替。5. as 多用于固定搭配中：as is often the case(这是常有的事)，as was expected(不出所料) ，as often happens(正如经常发生的那样) ，as is known to all(众所周知)，as has been said before(如上所述)，as is mentioned above(正如上面所提到的)等。注：which 代表整个句子，还可用于 in which case, at which point, on which occasion 等。如：I may have to work late, in which case Ill telephone you. 我可能得晚点下班，那样我会给你打电话的
