名词性从句一、定义：名词性从句在功能上相当于名词，是一个句子分别充当另一个句子的主语、表语、宾语和同位语，由此被称为主语从句，表语从句，宾语从句和同位语从句。
辨别下列从句属于哪种名词性从句并分析：1）Why they haven’t left yet is unclear.2）It was good news that everyone got back safely.3）Polly didn’t know which way she should go.4）I’m interested in who that tall man is.5）We all thought it good news that the fog had finally gone.6）My question is whether Polly can find her way home.7）The fact that Polly didn’t ask for the man’s name is a pity.总结：名词性从句主要由陈述句、一般疑问句、特殊疑问句充当。
1）陈述句充当名词性从句时，由that引导；2）一般疑问句充当名词性从句时，由if或whether引导从句；3）特殊疑问句充当名词性从句时，由疑问词本身做连词引导从句。
4）名词性从句的语序应使用陈述句语序，不可用一般问句语序。
二、引导名词性从句的从属连词及从句语序1.连接词that；功能1）不充当句子成分2）无词义3）只起连接作用。
2.if/whether;功能：1）意为“是否”，有词义2）不做句子成分3）起连接作用翻译:1）I know that he will come thisevening.___________________________________________2) Whether we will go there or not hasn’t been decided yet.______________________________3.连接代词：what(ever), which(ever), who(ever), whom(ever), whose(ver)功能：1）有词义2）引起从句3）且在从句中充当一定的句子成分，常做从句中的主语、宾语、表语和定语。
找出下列主从句的名词性从句，并确定从属连词在从句中的句子成分：1）What he said isn’t true.2) There are so many books that I don’t know which one I should choose.3) The question is who will come to help us.4.连接副词when(ever), where(ver), why, how(ever)以及how(ever)+adj./adv.组成的词组引导的名词性从句。
功能：1）连接主从句2）有词义3）在从句中作句子成分，可作从句中的时间状语、地点状语、原因状语、方式状语或表程度，如：how(ever)+adj./adv.等。
找出下列主从句的名词性从句，并确定从属连词在从句中的句子成分：1) I wonder how he managed to finish the work in such a short time.2) Where we will stay during o ur visit to Australia hasn’t been announced.3) He can’t answer the question how he got the money.4) The question is when we can get there.5.名词性从句的语序应使用陈述句语序，而不可用一般问句语序，其结构为：从属连词（that/whether/if/wh-疑问词）+陈述句语序。
三、名词性从句分类讲解Ⅰ.主语从句1.主语从句在复合句中作主语，其主句的谓语动词用单数。
填空并翻译：1) What excited us most __________(be) that he passed the exam.2) _______(be) what he told us true?3) What we need________(be) more time?2. that引导主语从句时that不可省，且一般把它移到句末，前面用it作形式主语。
找出主语从句且翻译：1) It is certain that she will do well in theexam._______________________________________2) It is no wonder that he looks pale.________________________________________________3.由连接代词（what除外）和连接副词引导的主语从句可以直接放在句首，也可以用it作形式主语，而把真正的主语放句末。
改变句型，用it作形式主语：1) How we will go there hasn’t beendecided.__________________________________________2) Whether he will attend the meeting or not makes no difference._________________________________________________________________ _____________4.what引导的主语从句一般不用it作形式主语的结构，其他连词皆可使用此结构。
判断正误：1) It is a book what he wants.2) What he wants is a book.5.如果含主语从句的主句是疑问式，则须用it作形式主语结构。
翻译：已经宣布飞机什么时候起飞了吗？6.if不可引起主语从句，而是用whether引起，表“是否”之意。
填空：1）____________________________________(我们是否要举行会议) hasn’t been decided.2) It is not know_______________________________________(他们是否要来).7.用it作形式主语，把主语从句后置的常用句型有：1)It+be+adj.+that-clause.(常见adj.:obvious,true,natural,surprising,good,wonderful,funny,possible, likely, certain, probable, etc.)英译汉：⑴It is certain that she will do well in theexam._____________________________________⑵It is probable that he told her everything.__________________________________________汉译英：⑴很明显他们非常需要帮助。
_________________________________________________________________ ___________注：这类主语从句中，若adj.为necessary, important, strange等，从句要用虚拟语气，从句的谓语动词一般为：(should)+do.翻译：⑴It is necessary that you (should) master thecomputer._______________________________⑵学生学好英语很重要。
_________________________________________________________________ __________⑶真奇怪，他竟然自杀了。
_________________________________________________________________ ____________2)Itis+名词词组(afact,apity,nowonder,anhonor,nosurprise,ashame,goodnews等)+that-clause.翻译：⑴很遗憾我们不能去。
_____________________________________________________________________ _______⑵他告诉了她一切，这并不奇怪。
_________________________________________________________________ ____________⑶难怪他看起来脸色苍白。
_________________________________________________________________ ____________3) It is done(said/reported/thought/believed/hoped/expected/decided/well-known)+that-clause.翻译：（1）据说总统已经到达北京。
_________________________________________________________________ ____________(2)It is said that Jack drives badly._________________________________________________________________ ____________(3)众所周知，地球围绕太阳转。
_________________________________________________________________ _____________分析下列从句：(1) It was reported that the US was under the terrorist attack.(2) As was reported, the US was under the terrorist attack.(3) What was reported was that the US was under the terrorist attack.4) It seems（似乎）/happens（碰巧/恰巧）/appears（似乎）/doesn’t matter （不重要，不要紧）/makes no difference（没有影响）+ that-clause.翻译：(1) It makes no difference whether he will attend the meeting or not._________________________________________________________________ _____________(2)我恰巧看过这部电影。