1.介词后面的that不能省。Pter is a good student except that he is sometimes careless.彼得是好学生，只是有时粗心。
2.并列连词and连接两个或两个以上宾语从句，and前面的that可以省略，and的后面的that不能省略。Everybody could see what happened and that Tom was frightened.大家都会看出所发生的事情并知道Tom非常害怕。My uncle says(that)he has servd here for twenty years and that he is going to retire next month.我叔叔说他在这儿工作已二十年了，下个月即将退休。
3.that引导的宾语从句位于句首时，that不可省略。That he ever said such a thing I simply don't believe.我简直不相信他曾说过这样的话。
4.主句谓语动词与that从句之间有插入语，that不可省略。He said that,if he could manag it,he would come for dinner.他说，如果他安排得好的话，他会来吃晚饭的。
5.宾语从句中有其他从属连词时，that不能省略。He told me that if it was necessary they would work all night.他告诉我，如果需要的话，他们就干个通宵。
I don't think he can do it better than me.我想他不会干得比我好。
I don't believe they have finished their work yet.我相信他们还未完成他们的工作。
I don't suppose he cares,does he我想他不会在意的，是吗?
提示：在下列情况下，宾语从句不否定转移：1.think等词前有副词和表示强调的do I really expect he wont fail the examination.我真希望他不会不通过考试。
I do think that he is not fair.我确实认为他是不公正的。
2.think等词和其他词构成并列谓语I think and hope that he won't cheat at cards.我想，也希望他打牌不会作弊的。
3.think等词作为插入语His decision is not wise,I think.我觉得他的决定并不明智。
注意：含有宾语从句复合句的反意疑问句①反意疑问句一般与主句一致。He said they were going to help me,didn't he?他说过他们要帮我，不是吗?
She told you that the mat was her own work,didn't she她告诉过你这个垫子是她亲自做的，是吗?
I suppose you're serious,aren't you我想你是当真的，不是吗?(不可用don't I)I don't suppose he's serious,is he我想他不是当真的，是吗?(不可用do I)
China is no longer what she used to be.今日的中国不再是过去的中国了。The question remains whether they will be able to help us.问题还是他们能否帮我们。
Itappears that he has a taste for music.看来他对音乐有一定的鉴赏力.
At that time,it seemed as if I couldn't think of the right word anyhow.当时，我似乎怎么也想不出一个恰当的字眼来。
B.as,as if∕though引导的表语从句He looked just as he had looked ten years before.他看起来还与十年前一样。
It sounds as if someone is knocking at the door.听起来好像有人在敲门。
C.because,why引导的表语从句I think it is because you are talking too much.我想这是因为你话说得太多。
That's because he didn't understand me.那是因为他没有理解我。(That's because强调原因)
That's why he got angry with me.那正是他对我生气的原因。(Tha's why强调结果)
The reason why I was sad was that he didn't understand me.我难过的原因是他没有理解我。
They were all very much worried over the fact that you were sick.对你生病这件事，他们都很焦虑。
Where did you get the idea that I could not come你在哪儿听说我不能来?
I have no idea whether he'll come or not.我不知道他是否来。
We haven't yet settled the question where we are going t spend our summer vacation.到哪儿去度暑假，这个问题我们还没有决定。
It is a question how he did it.那是一个他如何做了此事的问题。There is no doubt that we will win.毫无疑问我们会赢的。
Word came that Mr President would come and inspect ourschool himself.有消息说总统先生将亲自来视察我们学校。
This is our only request that this(hould)be settled as soon as possible.尽快解决这个问题，这是我们唯一的请求。
He made the suggestion that we go by train.他建议我们坐火车去。