from用作介词，用来表示做为起点的特定地点或时间，有从...起，从...来，免掉，因为等含义。可用来指定来源、起因、方法或用具。

1.从...起，始于

She is singing from morning to night.她从早唱到晚。

2.从;由

He rose from office boy to managing director in fifteen years.

他十五年里从办公室勤杂员升到总经理。

3.用来表示做为起点的特定地点或时间，

walked home from the station

从家走到车站

4.从...来;出自

He comes from Shanghai.他来自上海。

5.表示去除、免掉、阻止、剥夺等

The pill will relieve you from pain.这药丸将使你免受痛苦。

6.表示区别、比较

He is old enough to know right from wrong.他已长大,能够辨别是非了。

7.由于：用来指定来源、起因、方法或用具：

a note from the teacher

老师写的条

taking a book from the shelf.

从架子上拿本书