• it 作形式主语

  • 代替不定式

    ​ It is necessary to read these books. 注意形式主语 it 后面的 is

  • 代替 that从句

    ​ It is good that he wants to study.

  • 代替动名词

    ​ It is no use reading novels all day long.

• it 作形式宾语，不定式或that从句可以做完全及物动词的宾语，但是不能直接作不完全及物动词的宾语

  ​ I think it necessary to exercise on a daily basis.

• it 用于强调主语或宾语

  ​ It is I who love him.

  ​ It was his word that mede me angry.

• it 也可用于强调介词短语或状语从句，句型为 It is/was + 介词短语/状语从句 + that从句

  ​ It was because he was lazy that he failed.

• almost 是副词，译为“几乎”，不能做代词；most 译为“大多数的、最多的”时，为形容词，译为“最”时，为副词，译为“大多数”时，为代词；all 译为“所有的”时，为形容词，译为“全部”时为代词，此时可用 almost 修饰

• 反身代词可用来强调主语和宾语：I want to see the boss himself.

• that、those 用来代替出现过的名词，其中 that 表示单数名词、those 表示复数名词

• those who、those whom：Tell those who are late to come and see me.

• each other 译为“两者彼此”；one antoher 表示“三者及以上的彼此”；one after the other 译为“两者相继地”；one after another 表示“三者或以上相继地”

• either 表“两者中任一”；neither 表“两者皆不”；both 表“两者皆”；any 表“三者或以上任一”；none 表“三者或以上皆不”；all 表“三者或以上皆”

• one...the other... 表“一个...另一个...”，一共两个；one...another...the other... 表“一个...一个...另一个...”，一共三个；one...another... 译为“一个...另一个...”，非限定两个；some...others... 译为“一些...另一些...”，非限定两类；some...others...still others 译为“一些...一些...另一些...”，非限定三类；明确数词 one/two... the others/the rest 译为“若干...其他/其余...”