before与after的区别

Before 在英语中是一个比较常用的虚词，它既可作介词或副词用，也可作从属连词用。在近几年的高考试题中常常出现考查其从属连词用法的题目。下面就把其作为从属连词的用法归纳如下：

1. 表示“在…..之前就…..”。

Mary had finished her homework before her mother returned.

2. 表示“过了多久后才…….. ，动作进行到什么程度才……”

The man almost knocked me down before he saw me .

They walked about 30 miles to the west before they saw a village .

They worked day and night about three days before everything returned to normal .

3. 表示“来不及； 尚未…..就…”

Before I could get in a word , he had measured me .

He ran off before I could stop him .

She left the company before I could have a word with her .

4. 表示“刚…就…”

I had hardly sat down before the bell rang.

5. 表示“不知不觉就…..； 还没弄清就……”

Time passed quickly and three months went by before Aqiao knew it.

6. 表示“宁愿…，决不…，与其…，毋宁….”常与will 或would 连用。

I would die before I would tell

I’d shoot myself before I apologized to him.

I would / will die before I surrender .

7. 表示“否则；以免”

Do it now before you forget . I will write it down before I forget it .

8. 用于句型“it was +时间段+ before …” 表示 “过了多久才…”

It was three days before he came back. .

9. 用于句型 “ it was not long +时间段+ before …” 意为“不久就….”

It was not long before he sensed the danger of the position .

10. 用于句型“it will be(not )+时间段+ before….”表示“要过多久/ 不久…才…”

It will be half a year before you graduate from this school .

It will be not long before you find you are wrong .

after 没有before用法多，一般就是在...之后的意思！

before 在..之前
after 在..之后.

before 在……之前

after 在……之后