专题九
1．that引导的名词性从句
名词性从句
连接词that, whether, if引导的名词性从句 (1)that在名词性从句中不作任何成分，引导宾语从句时有时可以省略，引导主语从句、表语从句和同位语从句时不能省略。
I think that you should turn to the teacher for help.(that不充当任何句子成分，也无实际意义) 我认为你应该向老师寻求帮助。
(2)that引导主语从句时，常用it作形式主语，常见句型有：
①It＋be＋形容词(necessary/right/likely/unlikely/wrong/important/certain等)＋that从句 It is wonderful that all of you have passed the difficult exam! 你们都通过了这次很难的考试真令人高兴！
②It＋be＋名词(短语)(a pity/a shame/a surprise/no wonder等)＋that从句 It is a pity that you have missed the wonderful lecture. 你错过了这么精彩的演讲真遗憾。
③It＋be＋过去分词(said/told/reported/decided等)＋that从句 It is suggested that the lab building (should) be built next year. 有人建议实验楼明年修建。
④It＋特殊动词(seems/appears/happens/matters)＋that从句 It appears that they have made the same mistake. 好像他们犯了同样的错误。
[名师指津] 在以下主语从句中，常使用虚拟语气，即“should＋动词原形”形式，其中的should可以省略。
①It is necessary/strange/important/natural etc.＋that ... ②It is a pity that ...
③It is suggested/requested/required/proposed/desired etc. ＋that ...
(3)动词find, feel, think, consider, make, believe等后面有宾语补足语时，需用it作形式宾语而将that引导的宾语从句后置。
I think it necessary that we take plenty of boiled water every day.我认为我们每天喝大量的开水是很有必要的。
2．whether与if 引导的名词性从句
(1)whether引导的主语从句既可放在句首也可放在句末，但if引导的主语从句只能放在句末，且前面需用it作形式主语。
Whether it is true remains a question. 这是否是真的依然是个问题。
It is unknown if he will attend the meeting. 他是否会来参加会议还不清楚。
(2)whether与if引导宾语从句时，大多数情况下可以互换，后面直接跟or not时用whether，用于介词后引导宾语从句时也用whether。
We don't know whether or not she was ready. 我们不知道她是否准备好了。
I'm interested in whether you've finished the work. 我对你是否完成了这项工作感兴趣。
(3)whether可引导表语从句和同位语从句，而if则不可以。 The question is whether it is worth doing. 问题是它是否值得做。
The question whether the work was worth doing has not been decided.这项工作是否值得做的问题还没有确定。
1．连接代词引导的名词性从句 连接代词who, whom, whose, what, which等不但起连接作用，也在从句中作名词或代词所作的成分，如主语、表语、宾语、定语等。缺少连接代词，从句不完整。
What worries us most is who let out the secret. 最令我们担忧的是谁泄漏了秘密。 2．连接副词引导的名词性从句
连接副词when, where, why, how等不但起连接作用，也在从句中作状语，表示时间、地点、原因和方式等。
He didn't tell me when we would meet again. 他没告诉我什么时候我们再见面。 Go and get your coat. It's where you left it. 去把你的大衣拿来。就在你原来放的地方。
I have no idea how I can express myself clearly in English. 我不知道如何用英语清楚地表达自己。 That's why I want you to work there. 那就是我要你在那儿工作的原因。 3．“疑问词＋-ever”引导的名词性从句
“疑问词＋-ever”引导名词性从句时，有词意，并且在从句中充当一定的句子成分。 Whoever breaks the law should be punished.
连接代词和连接副词引导的名词性从句
无论谁触犯法律都应该受到惩罚。
Wherever children go makes their parents worry. 孩子们无论去哪儿父母都担心。
[名师指津] “疑问词＋-ever”还可以引导让步状语从句，但“no matter＋疑问词”只能引导让步状语从句，不能用来引导名词性从句。
Whatever (＝ No matter what) you do, you must do it well. 无论你做什么，都必须做好。
[命题点感悟] 单句语法填空 ①(2018·浙江11月高考)It is possible ________ caffeine may cause birth defects (缺陷) in humans, too.
解析：that it作形式主语，that从句为真正主语。
②(2017·天津高考改编)She asked me________ I had returned the books to the library, and I admitted that I hadn't.
解析：whether/if 句意：她问我是否已经把书还给图书馆了，我承认说我还没有还。分析句子结构可知，空格处引导宾语从句，且在从句中不作任何成分，只起连接作用；又根据句意可知此处表示“是否”，故用whether或if引导宾语从句。
③(2016·全国卷Ⅰ)My uncle is the owner of a restaurant close to ________ I live.
解析：where 分析句子结构可知，介词to之后为宾语从句，宾语从句中缺少地点状语，故用where引导。
④(2015·全国卷Ⅱ)As natural architects, the Pueblo Indians figured out exactly ________ thick the adobe walls needed to be to make the cycle work on most days.
解析：how 分析句子结构可知，空格处是一个宾语从句。空格后的thick为形容词，因此空格处应用副词，故填how。
⑤(2014·广东高考)I didn't understand ________ this would happen and my credit card had already been charged for the reservation.
解析：why 根据语境可知，“我”不知道/不明白为什么会发生这样的事情。不明白的一定是原因，故用why引导。
1．that和what的区别
that引导名词性从句时，在主从句中不充当任何句子成分，也没有任何含义；而what引导名词性从句时，在主从句中都要充当一定的句子成分，what可以分解成定语从句中的“先行词＋关系代词”，即常说的“先行词＋that/which/who”。
It's a shame that he has made such a mistake.
名词性从句易错点