所谓从句就是一个句子在另外一个句子里面做句子成分。
名词性从句定义：一个句子在另外一个句子里面当名词使用，称为名词性从句。分为：
1、 主语从句。他不爱读书让我很生气。
2、 宾语从句。她说她是一个老师。
3、 表语从句。这次环境污染事件的焦点是那家化工厂是否长期违规生产。
4、 同位语从句。我得到确切消息我们的队伍赢得了比赛。
名词性从句的本质相当于一个名词，名词能做什么，它就能做什么。
名词性从句需要引导词
He doesn’t like to study makes me angry.这是错的
That he doesn’t like to study makes me angry.这才对
名词性从句结构构成：
that从句，由陈述句变来，任何一个陈述句，前面加上引导词that，就构成that从句，作表语和宾语时，that可以省略。
If/whether从句，由一般疑问句变来。
疑问词从句，由特殊疑问句变来。
That everyone may receive a moderate education is an object of vital importance.
Many people pretend that they understand modern art.
The most surprising thing about it, however, is that it can land anywhere: one snow, water or even on a ploughed field.
No one could account for the fact that one of the boxes was extremely heavy.
That从句作主语时，为了使主干更紧凑，通常可用it作形式主语，而将真正的主语后置。
It was obvious that he was very embarrassed.
It is a curious coincidence that Mr. Page will have been teaching for a total of forty years.
复习consider、deem、think、find、believe这五个动词是宾补动词，构成第四大句型，表示“认为……是……”
I think health very important.
I think that we should speak English important.这是错的。改为：I think it important that we should speak English.此时不可采用宾语补语的常见的造句规则。
I think it necessary that you do it at once.
We find it necessary that we practice spoken English every day.
一般疑问句。Will he come tomorrow?
I don’t know will he come tomorrow. 这是错的。改为：I don’t know he will come tomorrow.
任何一个一般疑问句，前面加上引导词whether或if构成whether从句，但主语与be动词或助动词的位置还原。如果助动词为do/does/did，还原后将do/does/did去掉，后面的动词根据人称和时态变化。
Whether they would support us was a problem.主语从句
He asked if Mr. Gilbert’s operation had been successful and the doctor told him that it had been. 宾语从句
On the way home, he asked Jenny if she had enjoyed the speech.宾语从句，直接宾语
介词后及or not结构中，通常用whether
I worry about whether I hurt his feeling.我担心是否伤害了他的感情。
My sister is only seven, but she always tells me whether my pictures are good or not.
名词从句是特殊疑问句。When will he come?
I don’t know when will he come. 这是错的，改为：I don’t know when he will come.
疑问词从句的构成方法与whether从句一样，只是将whether换成疑问词而已，句子必须改为陈述句语序。
He then asked when Mr. Gilbert would be allowed to go home and the doctor told him that he would have to stay in hospital for anther two weeks.宾语从句，其中when作从句的状语。
The doctor’s have not yet decide how the woman died.
I have no idea what has happened to him.我不知道他发生了什么事。
造句练习十七：
1、 谁将负责这项工程还没有被决定(be in charge of)。Who will be in charge of the project hasn’t been decided yet.
2、 他要来参加这个会议已经使得我们每个人激动了。That he will come to the conference has excited every one of us.
3、 他告诉我们他们会帮助我们完成整个工作的。He told us that they would help us finish the whole work.
4、 我不知道（wonder）您是否能小声点。I wonder whether you would mind making less noise.
5、 我认为每天多喝水是必要的。I think it necessary that we should take plenty of water.
6、 我不知道（have no idea）他们什么时候回来定居。I have no idea when they will be back and settle down.
7、 我已经发现所有的票都已经卖光了。I had found that all the tickets had been sold out.
8、 问题是这部电视剧是否值得一看。The question is whether the TV play is worth watching.
