DOC《众所周知,which与as都可以引导定语从句,但它们有许多用...》

众所周知,which与as都可以引导定语从句,但它们有许多用法上的区别,现就此简要分析如下:

一、which与as引导非限制性定语从句的区别: 1.

Which只能放在主句后面,而as引导的从句位置相对较灵活,可在前,可在中,也可在后.例如: A)?? As he realized, I was very useful to him.(在前) B)?? Air, as we know, is a gas.(在中) C)?? He was a foreigner,as I know from his accent.(在后) 2.在which引导的定语从句中,谓语动词若是am, is, are则这些系动词不能省略;

而as后面若是这种情况,则可以省略.例如: A)?? He is a teacher, as (is) clear from his manner.(is可以省略) B)?? He said he had never seen her before, which was not true.(was不可省略) 3.当which引导的从句在意义上近乎并列关系时,可以用and this,and that代替,意思是 这件事 例如: A)?? He changed his mind, which(and this, and that)made me very angry.他改变了主意,这使我很生气. B)?? She has married again, which(=and this, and that)was unexpected.出乎意料的是,她又结婚了. 而as主要起与上下文连接的作用,表达说话人的看法、观点,并指出主句内容的出处或根据等,例如: C)Einstein, as we know, is a famous scientist.爱因斯坦,众所周知,是位伟大的科学家. D)As is announced in today'

s newspaper, we must improve our style of work.今天的报纸上说,我们必须改进工作作风. 4.作主语时,which既可以作系动词be的主语,也可以作实义动词的主语;

而这时as 只可以做系动词be的主语.例如: A)?? He married her, which was natural.(可用as代替which)他和她结婚,这是很自然的事. B)?? He won a/the Nobel Prize in chemistry, which made him illustrious. (不可用as 代替which)他获得了诺贝尔化学奖,这使他名扬天下. 5.当定语从句位于主句之后,纯粹表示主句所述内容,不带有 如……那样 的意思时,往往用which,而不用as.例如: A)?? They were invited to the state banquet, which(as)was a great honor to them.他们被邀请参加国宴,这对他们来说是莫大的荣幸. B)?? We had to sleep in our wet clothes, which was most uncomfortable.我们不得不穿着湿衣服睡觉,这简直太不舒服了. C)?? Mummy always treats me just like a baby, which I can'

t bear.妈妈老把我当成小孩对待,这让我无法忍受. 6.当定语从句有 如同……那样 含义时,用as比用which更常见,而这些从句几乎成为固定说法.例如: A)?? Things will turn out contrary to one'

s wishes, as is often the case.事与愿违,这是常用的事. B)?? As was natural, this inordinate hope was followed by an excessive depression.这种过分希望之后,接着是极度的沮丧,是很自然的事. C)?? Chaucer is buried in poet'

s Corner ,as might have been expected.正如人们已经预料的,乔叟被葬在 诗人角 . D)?? The material is elastic, as is shown in the figure.这种霉烂有弹性,如图所示. E)?? As we know(众所周知) F)?? As has been said above/before(正如前文所述) G)?? As has been pointed out(正如已经指出的) H)?? As might be imagined(可以想象得到) 7.当定语从句的关系代词指的是先行词本身时,只能用which.例如: A)?? These apple trees, which I planted three years ago, have not borne any fruit.这些苹果树是我三年前种下的,没结出任何果实. B)?? The Thames, which is now clean enough to swim in, was polluted for over a hundred years.泰晤士河,现在已经干净,可以在里面游泳,它曾被污染了一百多年. 8.带介词的典型的定语从句,必须用which,不能用as.例如: A)?? There is a great deal of oxygen around us, without which we could not live.我们周围有许多氧气,没有它我们就无法生存. B)?? The shed in our garden, in which we often played, has lasted for a long time.我们经常玩耍的花园里的那个棚子,已经有很长时间了.