主语从句是中学阶段的重点语法项目,也是高考的热点之一。为使同学们更好地掌握其用法,本文结合高考试题,对主语从句的考查热点进行梳理,以便帮助大家明确其命题特点,掌握答题技巧。

　　一、恰当选用连词

　　1. 考查连词that, whether, what等。

　　that引导主语从句时,只起连接句子的作用,本身没有词义,在从句中也不作句子成分,但通常不能省略。例如:

　　That the college will take in more new students this year is true. 今年这所大学将招收更多新生是真的。

　　whether引导主语从句时,表示主语从句意义的不确定性,在从句中不作句子成分,但有词义,作“是否”解。例如:

　　Whether he can finish his task on time is of great importance. 他是否能按时完成任务非常重要。

　　一般说来,已经确定的事情常由that引导,没有决定的事情常由whether引导。

　　what引导主语从句时,意为“……的事物”,相当于the thing(s) that。

　　[原题再现]

　　① ________ you don’t like him is none of my business.

　　A. WhatB. Who C. That D. Whether

　　② After Yang Liwei succeeded in circling the earth, ________ our astronauts desire to do is walk in space.

　　A. whereB. what C. that D. how

　　答案: ① C ② B

　　2.考查whatever, whoever, whichever, whomever等。

　　这些词在从句中不含疑问意义,它们引导主语从句时,whoever=the person who或anyone who;whatever=anything that;whichever意为“无论哪一个”。

　　[原题再现]

　　________ leaves the room last ought to turn off the lights.

　　A. Anyone B. The person C. Whoever D. Who

　　答案: C

　　3. 考查where, when, how, why, wherever以及how many / how much / how far / how long / how soon等。

　　这些词本身有词义,并在从句中作状语。例如:

　　How they will solve the serious problem has not been decided. 他们将怎样解决这个严重问题还没有决定。

　　Where we can look up his address is still a problem. 我们在哪儿可以查到他的地址还是个难题。

　　Why he did that wasn’t quite clear. 他为什么做那件事还不十分清楚。

　　How much water is flowing can be easily measured. 有多少水在流动很容易就能测出来。

　　二、it用来作形式主语

　　在某些情况下,可以由it作形式主语,而把真正的主语从句移到句子后面。

　　1. 谓语是seem, appear, be certain, be a pity, be a wonder, be one’s hope, be likely等词或短语时。

　　[原题再现]

　　The Foreign Minister said, “________ our hope that the two sides will work towards peace.”

　　A. This is B. There is C. That isD. It is

　　答案: D

　　2. 用于It is suggested / required / ordered / demanded that...句型中,动词为表示命令、建议、要求等意义的词。主语从句应使用虚拟语气,谓语动词用“should + 动词原形”,should可以省略。例如:

　　It is suggested that you (should) spend more time in studying English. 你应该花更多的时间学习英语。

　　3. 用于It is important / natural / necessary / impossible that...句型中,主语从句应使用虚拟语气,谓语动词用“should + 动词原形”的形式,should有时有感情色彩。例如:

　　[原题再现]

　It is necessary that a college student ________ at least a foreign language.

　　A. masters B. should master C. mastered D. will master

　　答案: B