限定从属分句就是我们传统意义上的从句。从句依附于主句�，不能独立成句但是具有主语与谓语部分。
从句内容的分类
1. 从句作为主语
例：What he needs is some rest.
如果从句过长，需要用it作形式主语�。
例：Whether technology can be considered as the “motor of society” is a chicken and egg debate.
如果将从句用作主语的话，容易造成头重脚轻的感觉，这时候需要用it做形式主语，改成
It is a chicken and egg debate whether technology can be considered as the "motor of society”.
2. 从句作直接宾语�（与谓语动词的关系不如NP紧密，可插入其它成分）
①decide that…
例：We decided that we would do it together.
②wonder whether/if/wh- phrase…
�例：I wonder whether/if I am good enough.�
I wonder who did not come to work.
③mention to NP that…�（这里的to NP是一个可省略的补语，that从句才是直接宾语。）
�例：He mentioned (to me) that he was writing it.
④tell NP that…（这里的NP是间接宾语；that...从句是直接宾语�）
例：She told me that she had started her application.
可以将间接宾语变成主语，改为：I was told that she had started her application.
⑤ask/show/teach/tell NP whether/if/wh-phrase…
例：I asked her whether she would like to join us.�
He told us what a great job we had done.�
The mother is teaching her boy what to do.
⑥consider it NP/AdjP that/wh-phrase…（这里的it是形式宾语）
例：Some scientists consider it possible that AI would take the interpreters’ places one day.�
We consider it a major concern how the problem is dealt with.
3. 从句作补语从句
由谓语动词引出的，但是不属于直接宾语、间接宾语或表语补足语的从句被称为补语从句。
①persuade NP that…
例：We persuaded them that we could do it.
②remind NP whether/if/wh-phrase…
�例：It reminds me whether I am on track.
③It seem (+PP) that/as if…
例：It seems (to me) that there is still enough room.
4. 作为主语相关的表语补足语�句式：be that/wh-phrase…
�例：The first myth is how this is possible.�
What I wonder is whether we could finish it.
5. 从句作为修饰语—用于在省略if时标记该分句为从句：�（一般需要倒装�）
例：Had I spent more time on study, I should now be doing my PhD.�
Should I be accepted, I will spare no efforts to do researches.
关系从句/定语从句的作用：�提供与先行词相关的信息
关系从句的分类
1. wh- 从句
关系代词：�who, whom, whose, which 其它：when, where, why
例：In the period when he was writing, he reached the climax of his career.
�There is no fixed place where it is kept.�The reason why… is because…
which可以修饰整个主句
例：In the presence of so many people he was little tense, which was understandable.
2. 非wh-从句（即that从句）
例：The work that we do is nothing special.
3. 限定性定语从句和非限定性定语从句
非限定性从句有逗号隔开�比较：The pizza which you ordered is finished.�Peter, whom you met in London, is now back in Paris.
that只用于限定性定语从句，which则二者皆可
4. 自由定语从句�
自由关系代词用于自由关系从句（取代NP的位置）。它的特点是没有先行词。
What > who(m), which
例：What you do is just to switch it off.
whatever, who(m)ever
例：Is it worth complaining to whoever was in charge?
掌握好从句的用法，是写好一篇文章的基础。上述内容将介绍了两类从句的基本内容和用法，将上面的内容掌握好，对自己雅思写作的基础做个铺垫。