从属连词that, if, whether;
连接代词who, whoever, whom, whomever, which, whichever, what, whatever, whose;
连接副词where, when, why, how。
其中, 从属连词只起连接作用, 在从句中不充当任何句法成分,
That Owen should have married his cousin is not at all surprising. (主语从句)
The fact is that he didn’t go to the dinner party. (表语从句)
I don’t know if he will attend the meeting. (宾语从句)
Have you heard the news that Mary is going to marry Tom? (同位语从句)
1. 在含有主语从句的复合句中, 为保持句子平衡, 常用it作形式主语,而将真正的主语从句置于句末.
It’s well-known that water is indispensable to life.(形式主语)
2. 为保持句子平衡, that引导的宾语从句也常用it代替, 而将真正的宾语从句置于主句句末。这常常出现在主句有形容词或分词作宾语补足语的情况下。
He made it quite clear that he preferred to live here.
3. 从属连词whether和if都作“是否…”解, 但if不可引导主语从句和表语从句。whether可与or(not)连用, 而if不可以。
I don’t know whether (if) she is at home.
Whether she comes or not makes no difference.
4. that和what引导名词性从句的区别: that在从句中不充当成分,而what在从句中充当一定的成分, 如主语、表语、宾语等。that可省略, what则不可省。
He always means what he says.
She suggested (that) he do it at once.
5. 同位语从句大多由从属连词that引导, 常跟在下列名词后面, 如fact, idea, opinion, news, hope, belief等, that不可省。同位语从句一般用来解释说明这些名词的具体含义和内容。
We are familiar with the idea that all matter consists of atoms.
The news that we are invited to the conference is very encouraging.