1. He promised that if he came back early, he would cook for her.这句子有两个谓语promised和would cook？
【答】这里的that if he came back early, he would cook for her 是宾语从句，这个宾语从句本身又是含有条件状语从句的主从复合句。promised是主句的谓语动词；would cook 是宾语从句中主句的谓语动词。
2.如何区分it所在句子是形式主语还是强调句？
比如：It is not immediately clear whether the financial crisis will soon be over.这里是形式主语。
It is imagination that makes the world colorful.这个是强调句，it作什么成分？
【答】如果去掉It is 和 that 这3个单词后，剩下的单词能够组成一个完整而且正确的句子（必要时词序可以变动），原来的句子就是强调句。这里的it 是主语。
3.The thought of going back home was all that kept him happy while he was working abroad.
这里all that是不是相当于all为先行词，that为关系代词做主语？all that等于what？
【答】在这里的all that中，all为先行词，that为关系代词做主语。all为先行词时，that（关系代词）也可以作宾语，如：This is all (that) I know.
4. The traditional view is ____ we sleep because our brain is programmed to make us do so.
A.when B.why C.whether D.that
这几个选项都能引导表语从句，为什么只能选D项that呢？
【答】如果选择A.when B.why 或者C.whether ，则 is 后面是两个从句，而且整个句子含义不清，所以是错误的。这里的that （无词义）引导表语从句，这个表语从句本身是一个含有原因状语从句的复合句。
