A．当主句谓语动词带有两个或两个以上宾语从句时，可以省略第一个that，其他不能省略。
eg．I believe（that）you have done your best and that things will get better．
B．当it作形式宾语时
eg．She made it clear that she had nothing to do with him．
C．当宾语从句前置时
eg．That our team will win，I believe．
[编辑本段]宾语从句（版本四）
一、定义和宾从例句分析
宾语从句就是一个句子作动词或介词的宾语。
A 作动词的宾语:
I heard the news.
主语 谓语动词 名词作宾语
I heard that he would come here later on.
主语 谓语动词 一个句子作宾语---宾语从句
B 作介词的宾语:
He said nothing about the plan.
主语 谓语动词 代词作动词的宾语 介词 名词作介词的宾语
He said nothing about who broke the window last night.
主语 谓语动词 代词作动词的宾语 介词 一个句子作介词的宾语
二、带有宾语从句的复合句的构成
带有宾语从句的复合句就是用连接词把一个主句和一个宾语从句连接在一起。连接词有：that(可省略)，what, who, when, where, why, which, if, whether, how.
1 He suggested (that) we should clean the corridor every day.
宾语
2 He told me (that) he would leave Dalian airport at 8pm.
间接宾语 直接宾语
3 He told me where he was going to travel that summer.
间接宾语 直接宾语
4 He wanted to know what the manager had said at the meeting.
who hadn't passed the exam.
when she would leave this building.
why she cried last night.
where she was going to study.
which student was his partner in the short play.
if (whether) Tom could play basketball with him that morning.
how she managed to solve the problem.
why water flows from a high position to a lower position.
在例子4中，当主句是过去时态时（一般过去时，过去进行时，过去将来时，过去完成时），从句根据作文-地带提供不同情况必须使用过去时态的一种，（大自然的现象和真理除外）。
5 He is wanting to know what I can cook for dinner.
who broke the window yesterday.
when I can have a holiday.
why I failed the exam yesterday.
where I should have dinner with my friend tonight.
which book is the best one.
if (whether) I have passed the exam.
how my cat escaped from the room last night.
在例子5中，当主语是现在时态时（一般现在时，现在进行时，一般将来时，现在完成时），从句可根据作文-地带提供不同情况使用各种时态。
三、注意
A 宾语从句必须用陈述语序。
False: He is wondering when can he finish this difficult job.
Right: He is wondering when he can finish this difficult job.joozone.com