it和that的用法区别
one,it,that的用法区别
It 有四种用法
1、人称代词：指代已知的或已经提到的事物，包括无生命物体，性别不详、不知或不相关的有生命物体。如：
Pass it to me. 把它东西给我递过来。
Who is it behind the door? 门后那个人是谁呀？
2、非人称代词：指代时间、气候、距离、情况以及度量衡等。如：
It is Tuesday today. 今天（时间）是星期二。
It was cold that day. 那天（天气）很冷。
It is not that far. （距离）不算太远。
3、先行代词：指代为了平衡句子结构而后置的作主语或宾语的不定式短语、动名词短语或从句。如：
It is important for us to do it. 我们做这件事很重要。
It is helpless crying over spilled milk. 无益的后悔是没用的。
We found it necessary to pay a visit to him. 我们觉得有必要去拜访他。
4、强调代词：在句型it is … that 中强调主语、宾语或状语部分。如：
It was yesterday that he gave someone a ring. 那是昨天他给人打过电话。
That 的主要用法如下：
1、指代已提过的事件、行为或时间。如：
After that, he became a teacher. 从那以后，他成了教师。
2、指代较早或较远事物。如：
That is for sale; this is not. 那个是出售的；这个不是。
3、指代上文提到过词或短语的意思。如：
He was fed up, and that to a great degree. 他已吃饱，而且相当撑。
4、用作关联词，引导名词性从句（主语、宾语、表语和同位语）、定语从句和状语从句（目的、结果、原因等）【例句从略】
This 的主要用法如下：
1、指代当前、邻近或刚提及的人或物，如：
said he'd be back before this. 说他会在这之前回来。
2、指代即将谈到的事，如：
Now don't laugh when you hear this. 听了这个你不要笑。
3、指代较近的人或事物，如：
This is mine and that is yours. 这个是我的，那个是你的。
It做形式主语，代替由不定式，动名词短语或是从句所表示的真正的主语。如It’s no use talking to him about it. It做形式宾语，代替一个由不定式，动名词，或是宾语从句，如I think it no use arguing with him. it可以指季节,时间, 距离 如It was mid summer. It’s only five miles. 同时在强调句中，It + be + 要强调的部分+ that(who, whom) + 句子其他部分 .这个句型很重要，记住即可。 that有些固定的搭配 如 so that ，such that。 that 用作连词，引导名词性从句,状语从句和强调句。 1. that名词性从句。 ①引导宾语从句。及物动词后的引导词that可省略。 I didn't expect (that) he could win the championship. The teacher pointed out that Tom was not working hard enough. ② 引导主语从句。通常采用it作形式主语的句型。 That the earth goes around the sun is known to everyone. （It is known to everyone that the earth goes around the sun.） ③引导表语从句。 The trouble is that we are short of money. ④引导同位语从句。 引导同位语从句的that和引导定语从句的that是不同的。前者只起语法作用，在从句中不作任何成分；而后者在定语从句中作主语、宾语或表语。举例说明： The news that he resigned from office surprised us. The idea that he holds is very common nowadays on campus. 2. that引导状语从句 ①引导目的状语从句。 Bring it nearer that I may see it better. ②引导结果状语从句。 What have I done that he should be so angry with me? ③引导原因状语从句。 I am afraid that I will fail in the driving test. ④引导让步状语从句。意为“虽然、尽管”。 Difficult that/as the task was, they managed to accomplish it on time. ⑤引导条件状语从句。意为“假使、假设”。 Supposing that you were in my position, what would you do? On condition that you were lost in the desert, you should ask for help as soon as possible.
