THAT的用法集锦
（一）that用作指示代词,指代某人或某物,或指上文提到的人或事物(单数名词)."那个"
（二）that用作形容词限定单数名词,"那个,那",或作副词修饴形容词或副词,表程度."那么"
（三）引导从句的that.
1.与有关词构成短语,如 so that(以便,以致),so...that(如此…以致),such…that(如此…以致),in order that(以便),for fear that(以免),on condition that (假设),now that(既然),in that(因为)等,引导的状语从句,且that不可省.
2.that用作从属连词,引导名词性从句,且在从句中没有意义,也不充当成份,引导宾语从句时有时可以省略,但引导主语从句,表语从句和同位语从句时一般不省略.要注意从句的位置. 有时用it作形式主语,把从句置于谓语动词之后时,that可以省略

3.that用作关系代词,引导限制性定语从句,替代其前面的先行词,充当从句的主语和宾语,其先行词既可是人也可是物.
当它作从句的主语时,that不可省.但如作从句的宾语时,that可省略
（四）用在强调句型 It is/was...that结构中,替代被强调部分,没有意义,但that不可省.
（五）含有that的常用短语和惯用语.
That is to say (作插入语)那就是说,即
That's all right.(回答致谢或致歉)不必谢,没关系.
That's it.对了,就这样.
That will do/That'll do.够了,行了.
That rings the bell.答对了.
Upon that 于是,立刻 如,Upon that they left.
So that's that. 就这样决定了.
That's all.(讲话结束语)完了.
That's great!太好了,好极了.