1、四、语法详解主语从句主语从句有两种：1.主语从句（ the subject clause）在句中作主语，有以下两种结构（1）主语从句位于句首。Who kept the door open all night was unknown.谁让门整夜开着，没人知道。(2)主语从句位于句尾，使用先行词 it 作形式主语。It was right that the temple was rescued.重修寺庙是正确的。主语从句能用 it 作形式上的主语。常见 it 作形式主语的句型有：It +be +形容词（ clear, true, natural, good, possible, likely, c
2、ertain, wonderful, fancy, etc）+ that 从句。It is certain that she will do well in her exam.她肯定会考好。It + be+名词词组（no wonder, an honour, a pity, no surprise, a good thing, etc）+ that 从句。It is a pity that we cant go.真可惜我们不能去。It + be +过去分词（said, reported, thought, expected, decided, etc）+that 从句。It is said t
3、hat Mr. Green has arrived in Beijing.据说格林先生已抵达北京。It+ seem/ happen 等不及物动词及短语+ that 从句。It happened that I was out that day.碰巧那天我不在。It + doesnt matter (make no difference, etc)+ 连接代词或连接副词引导的主语从句。It doesnt matter whether she will come or not.她来不来并不要紧。It makes no difference where we shall have the meetin
4、g.我们在哪儿开会并不要紧。当 that 引导主语从句出现在疑问句中时，要以 it 作形式主语，而把主语从句后置。Is it true that the scientist will give us a lecture next week?那位科学家下周要来给我们作报告，这是真的吗？2.主语从句的连接词可以分为以下三类（1）that, whether (if)连接词 that 本身没有意义，不作句子成分，只表示从句的开始，位于句首时 that 不能省略；whether (if) 尽管不充当句子成分，但是含有“是否”的意思，可以加上“or not”，其语义不变。Whether 和 if 也有不同
5、的用法，如果主语从句位于句首则必须用连接词 whether;不用 if。Whether we can control the floods is still uncertain.我们是否能控制洪水，目前还不肯定。（2）what, who（m）, which, whose, when, where, why, how 在这一类连接词中，除了引导主语从句之外，又分别起代词、副词或形容词的作用，在从句中分别作主语、宾语、表语、状语和定语。因此 what, who(m), which 又称为连接代词； when, where, why, how 又称为连接副词；whose, which, what 又
6、称为连接形容词。Who will do it doesnt matter.（连接代词 What 在从句中作 need 的宾语）谁做这件事都没有关系。What we need is more water.(连接代词 What 在从句中作 need 的宾语)我们所需要的是更多的水。When we start the work is an important question.(连接副词 When 在从句中作时间状语)我们什么时候开始这项工作是个很重要的问题。（3）whatever, whoever, whomever, whicheverwhatever 等连接词与 what 等连接代词的用法一样
7、，只是具有较强的语义， “凡是；不管；无论”等意思。Whatever he said wasnt true.他说的任何事情都不是事实。Whichever book you choose is yours.无论你选中哪本书都归你。活学巧用单项填空1._ David says sounds right to Helen. Thats why she has made up her mind to leave with him _ happens.A.Whatever; whateverB.No matter what; whateverC.No matter that; no matter tha
8、tD.Whatever; however提示：句意为：“无论大卫说什么，对海伦来说的原因都是正确的，那就是为什么她下定决心不管发生什么事一定要跟着他离开的原因” 。whatever 引导主语从句“无论什么 ”no mater whatever 引导让步状语从句，故排除 B、C 两项。however 是“无论怎么样”不符合题意，故排除 D 项。答案：A2.It worried her a bit _ her hair was turning grey.A.while B.that C.if D.whether提示：此句为 it 作形式主语，真正的主语是 her hair was turning
9、grey。引导词 that 无实义，不能省略。答案：B3._ we cant join in the party.A.It is a pity B.That is a pityC.It is a pity that D.It is pity提示：主语从句位于句尾，使用先行词 it 作形式主语。 It + be +名词词组（no wonder, an honour， a pity, no surprise, a good thing）+ that 从句，其中 that 不能省略。故排除A、B、D 三项。答案：C4.Was it _ he said or something that he did
10、 _ made her cry so sadly?A.what; that B.that; whichC.that; what D.what;/提示：此句考查了强调句和主语从句。首先 he said 后面缺少了宾语。made 前缺乏主语，故第一个空应填 what 充当主句和从句成分的作用。第二个空考查强调句 it is/was that 结构，去掉 it is/was that 后剩下的是一个完整句子。答案：A5._ made the school proud was _ more than 90% of the students had been admitted to key univer
11、sities.A.What；because B.What； thatC.That； what D.That； because提示：句中 was 前面为主语从句，主语从句中 made 前面缺少主语，故第一个空只能填 What 充当连接词；补充句子成分。第二个空 was 后面引导词是 that 引导的表语从句。答案：B6._ well go camping tomorrow depends on the weather.A.If B.Whether C.That D.Where提示：if 不能放在句首引导定语从句。句子意思为：“我们明天是否去露营将取决于天气。”本题考查 whether 引导的表语从句，表“是否”之意。答案：B7._ fashion differs from country to country may reflect the cultural differences from one aspect.A.What B.That C.This D.Which提示：may reflect 之前的为主语从句，主语从句中 fashion 为主语，differs 作谓语，“country to ”为宾语。that 引导主语从句放在句首，无实义，不能省略，故选 B。答案：B
