1、which 与 as 引导非限制性定语从句的异同which 与 as 一样，都可以引导非限制性定语从句，它们既有相同之处，也有差别。因此在实际运用中容易混淆。它们的某些用法在高考中也会考查。一相同点。两者引导非限制性定语从句时，可指代主句中的部分或整个句子的内容，在从句中做主语，宾语或表语，位于主句之后有时可互换。The meeting was put off, as /which was exactly what we wanted.He was a doctor, as/which I knew from his manner.二 不同点1. as 可指其前后主句提到的事实或情况，因此引导
2、的非限制性从句位置比较灵活，which 可以放在主句前后，也可插入主句之中；而which 引导的非限制性从句只能位于主句之后。As is known to all, fish cant live without water.Air, as we know, is gas.2.在非限制性从句中，which 后的 be 动词不可省； as 而后的 be 动词可以省略。She told me she won the match , which was a lie.The material is elastic, as (was) shown in the figure.3. which 在非限制性定
3、语从句做主语时可用各类动词做谓语；而在非限制性定语从句做主语时，谓语常用连系动词，如 be, seem, become 等，一般不用其他行为动词。He saw the girl, which delighted him.He didnt say anything at the meeting , as/which seemed very strange.4. 如果主句中叙述的事情与从句所涉及的意向一致，多用 as，用以对主句的意义进行补充；如果不一致，就用 which She has married again, as was expected.He broke the rules again
4、, which was unexpected.5.如表示“如同。 。 。那样，按照，正如”含义，常用 as，这里 as 主要起与上下文联系的作用，表达说话人的看法，并指出内容，出处和根据等，常用的结构有 as we know（众所周知）as often happens（正如常发生的那样）as is often the case（情况常常如此）as we all can see（正如我们看到的）be+announced/expected/known/imagined/mentioned/said/shown/reported（正如所。 。 。 ）等。这些结构常放句首，偶尔也可以放句中或句末As
5、is known to all, China is a developing country.Kate was late for school , as often happened.6.在非限制性定语从句中关系代词指代主句中某一个单词时，常用which My brother enjoyed playing basketball , which he really plays well.Beijing , which he was born in, is our capital.7.在非限制性定语从句中“介词+关系代词（介宾代物） ”中关系代词只能用 which The Travel Agen
6、cy, with which our company has been dealing for several years, has opened for new branchesAir is a mixture of gases, of which oxgen forms 21 percent.8.有时用 case, point, time, situation 或 reason 等抽象名词来总结主句的内容，可用“介词+ which +抽象名词”构成从句Ten years of hard work changed her greatly , for which reason he could
7、 hardly recognise her at first sight.The machine may be out of order , in which case it will be repaired at once.9.在非限制性定语从句关系代词用以代表主句中谓语的整个概念，从句中的谓语动词是否定形式时，常用 which He can write a letter in English, which I can not.Metal will bear beating with a hammer, which a stone willl not 10.在非限制性定语从句关系代词代表前面
8、主句中的宾语从句时，常用 which He said he had passed the exam , which was untrue.1.The owner of the cinema needed to make a lot of improvements and employ more people to keep it running ,_meant spending tens of thousands of pounds.A.who B.that C.as D.which2.Jim passed the driving test,_surprised everybody in th
9、e office.A.which B.that C.this D.it3.The road conditions there turned out be very good,_was more than we could expect.A.it B.what C.which .that4.Mark was a student at this university from 1999 to 2003,_he studied very hard was made Chairman of the Students Union.A.during which time B.for which time
10、.during whose time D.by that time 5.The Science Museum ,_we visited during a recent trip to Britain , is one of Londons tourist attractions. A.which B.what C.tha tD.where6.The Beatles,_many of you are old enough to remember, came from Liverpool.A.what B.that C.how D.as7._I expained on the phone , yo
11、ur request will be considered at the next meeting.A.When B.After C.Wha tD.Since8._is often the case, we have worked out the production plan.A.Which B.When C.What D.As9. _has been announced , we shall have our final exams next month.A.That B.As C.It D.What10. _is reported in the newspaper, talks between the two countries are making progress.A.It B.As C.That D.WhatDACAA DCDBB
