——从一道高考题谈起
2001年高考中有这么一道单项选择题：
________ is known to everybody, the moon travels round the earth once every month.
A. It B. As C. That D. What
此题的答案为B, as 在这引导一个非限制性定语从句，修饰后面这句内容。但有学生不明白为什么不选A或D。这就说明他们对一些句型结构分辨不清，我们把题目做以下变化：
(1) ______ is known to everybody that the moon travels round the earth once every month.
(2) ______is known to everybody is that the moon travels round the earth once every month.
题答案为A。it作形式主语，真正的主语是that引导的从句。再如：
（2004北京）The Foreign Minister said，“ _________ our hope that the two sides will work towards peace.
A. This is B. There is C. That is D. It is (D)
(NMET1995)____ is a fact that English is being accepted as an international language.
A. There B. This C. That D. It (D)
而(2)题答案为 D，what在此引导一个主语从句，它在从句当中又充当主语，而后面的that引导的从句则是表语从句。
再如：(2004北京) ________ is reported in the newspaper, talks between the two countries are making progress.
A. It B. As C. That D. What (B)
(2004江苏)________ is often the case, we have worked out the production plan.
A. Which B. When C. What D. As (D)
(1999上海) is mentioned above, the number of the students in senior high school is increasing.
A. Which B. As C. That D. It (B)
所以易混句型是广大学生学习中的一个难点，也是高考中的一个重点内容，不但在单项选择题中出现，而且在短文改错中，完型填空中也有涉及。笔者连续任教高三毕业班，根据对教材，《教学大纲》、《考试大纲》以及对历年的特别是近６年的练习题、高考模拟题、高考试题进行分 析、研究和归纳，总结出以下常见易混句型，加以辨析，供同学们参考，不足之处请同行指正。
一、(1) It was 3 years ______ he came back.
(2) It was 3 years ago ______ he came back.
(3) It is 3 years ______ he came back.
A. since B. that C. when D. before
辨析：(1)题答案为D.意为“过了三年，他才回来。”It在此表时间，特别注意，主、从句时态的一致。再如：But it will be more than 100years before the country begins once again to look as it did before.(SEFC, SB2A ,P64)此复合句中的从句中用一般现在时表将来动作。
(2004福建)Scientists say it may be five or six years ______ it is possible to test this medicine on human patients.
A. since B. after C. before D. when (C)
题答案为B。是强调句型。此句型特点是可以还原。如此句可还原成He came back 3 years ago.再如：
(NMET2000) It is the ability to do the job______ matters not where you come from or what you are.
A. one B. that C. what D. it (B)
(NMET1998) It was about 600 years ago ______ the first clock with a face and an hour hand was made.
A. that B. until C. before D. when (A)
题答案为A. since表从过去到现在为止。
二、(1)It was midnight _____ he returned home.
(2)It was at midnight ______ he returned home.
A. when B. that C. before D. since
辨析：(1)题答案可为A. when引导时间状语从句。“It”在此表时间。再如：
（NMET2000） It was an exciting moment for these football fans this year, ____for the first time in years their team won the World Cup.
A. that B. while C. which D. when (D)
(1)题答案也可为C,意为“他还没回到家就已经是半夜了。” 再如：
(2004天津) It was evening ______ we reached the little town of Winchester.
A. that B. until C. since D. before (D)
(2)题答案是B。强调句式。
三、(1) A team of 15 Indian experts are organizing a workforce of 400 Cambodians, most of _____ women.
(2) A team of 15 Indian experts are organizing a workforce of 400 Cambodians, and most of _____ women.
(3) A team of 15 Indian experts are organizing a workforce of 400 Cambodians, most of _____are women.
A. them B. them are C. whom D. that
辨析：(1)题答案选A.为独立主格结构，起补充说明的作用。Most of them 与women构成逻辑上的主谓关系。
(2)题答案为B. and连接两个并列句。
(3)题答案为C. whom引导一个非限制性定语从句，起补充作用。再如：
(NMET1990) He paid the boy ＄10for washing ten windows, most of _____hadn’t been cleaned for at least a year.
A. these B. those C. that D. which (D)
四、(1)______ hard he works, he won’t succeed.
(2) Hard______ he works, he won’t succeed.
(3)______ he works hard, he won’t succeed.
(4)______his hard work, he won’t succeed.
(5) He works hard; he won’t succeed, ________.
A . although (though) B. However (however) C. As (as)
D. In (in) spite of E. Although (although)
辨析：(1)题答案为B。however hard等于No matter how hard引导让步状语从句。再如：(NMET 1999) We’ll have to finish the job, _____.
A. long it takes however B. it takes however long
C. long however it takes D. however long it takes (D)
（NMET1995）If we work with a strong will, we can overcome any difficulty,_____ great it is.
A. what B. how C. however D. whatever (C )
（2004湖北）You should try to get a good night’s sleep ______ much work you have to do.
A．however B. no matter C. although D. whatever (A)
(2)题答案为A或C。as与 though引导让步状语从句用倒装语序。再如：
(2001上海)______, I have never seen anyone who’s as capable as John.
A. As long as I have traveled B. Now that I have traveled so much
C. Much as I have traveled D. As I have traveled so much (C)
(3)题答案为A或E。引导让步状语从句。再如：
(2003北京春季)Mr. Hall understands that ______ math has always been easy for him, it is not easy for the students.
A. unless B. since C. although D. when (C)
(4)题答案为D。in spite of …为短语介词，后接名词，做让步状语。
(5)题答案为A或B。though与 however做副词，意为“然而，却”。
五、(1) Is this school ____ you visited the other day?
(2)Is this this school ____ you visited the other day?
(3)Is this school ____ you worked two years ago?
(4)Is this the school ____ you worked two years ago?
A. which B. where C. what D. the one E. in which
辨析：题(1)答案为C或 D。选C，what引导表语从句，在从句中做宾语，选D，the one做先行词， you visited the other day为定语从句。再如：
(2004天津) A modern city has been set up in ______ was a wasteland ten years ago.
A. what B. which C. that D. where (A)
(2003春招)—Are you still thinking about yesterday’s game?
---Oh, that’s _____.
A. what makes me feel excited B. whatever I feel excited about
C. how I feel about it D. when I feel excited (A)
(2002上海)Perseverance is a kind of quality ---and that’s ____ it takes to do anything well.
A. what B. that C. which D. why (A)
(2)题答案为A。 which 引导定语从句，在从句中充当 visited宾语。再如：
(2003北京)York,_____ last year, is a nice old city.
A. that I visited B. which I visited C. where I visited D. in which I visited (B)
(3)题答案为B，where引导表语从句，在从句中做状语，可译为 “……的地方”. 再如：
（NMET2004）You are saying that everyone should be equal, and this is ______ I disagree.
A. why B. where C. what D. how (B)
(4)题答案为B或E，引导定语从句，在从句中充当状语。再如：
（2004湖南）I work in a business ______ almost everyone is waiting for a great chance.
A. how B. which C. where D. that (C)
(2003上海)I can think of many cases ____ students obviously knew a lot of English words and expressions but couldn’t write a good essay.
A. why B. which C. as D. where (D)
(2002北京)We will be shown around the city, schools, museums and some other places, _____ other visitors seldom go.
A. what B. which C. where D. when (C)