before当连词和介词分别放在什么位置

before作连词,是从属连词连接时间状语从句,

在...之前,与after相反.例如：

*He had been a soldier for three years before he came to our city .

*She had learnt 2000 English words before she went to the USA.

before 作介词,分三种：

1）表时间,这和上面相似.

*She left the office before 9 o'clock.

*I finished studying English before midnight.

区别就是:连词+从句；介词+名词.

2）表顺序,第一、第二、...,也与after相反

*ZhangHong goes before me.

*There are five man before her.

3)表位置,（较不常用）也与after相反

*The car stops before my house.

*The tall tree stands before our school gate.

一般英语里用in front of...behind...来表示位置的前后.

*The car stops in front of my house.

*The tall tree stands in front of our school gate.