一、都可以表示时间，但是所表示的范围不同

  1. 表示具体时间或者年龄时用at

    例如：at 6 o'clock, at the age of five

  2. 表示上下午，或者月年的时候用in

    例如：in the morning, in 2017 ,in February

    in+时间段表示多久以后/以内

    例如：in ten minutes

  3. 表示星期，特定的日期或具体某一天用on

    例如：on Sunday, on Teachers' Day

    on the third of June,

    on也可表示在具体某一天上下午

    例如：on the morning of May , on Monday afternoon等

二、都可以表示地点位置

at 通常指小位置，in 指大位置，on指在某物表面

例如：at the station, in Beijing, on the table

三、in the tree与on the tree区分

in the tree 指树外之物，也就是后进入的

例如：There is a bird in the tree.

on the tree 指树中之物，也就是树上自己长出来的

例如：There are many apples on the tree.

四、强化习题

( )A lot of students in our school were born____ May,1998.

A.in B.at C.on D.since

() She suddenly returned____a rainy night.

A.on B.at C.in D.during

() My grandmother was born____Oct.12,1964.

A.on B.in C.at D.of

() The train is starting___ten minutes.

A.in B.at C.for D.still

()Tom does his exercises____ six _____the evening.

A.on;to B.at;in C.by;of D.at;on

()We wake up very early____the morning of Christmas Day.

A.in B.on C.for D.at

答案：A A A A B B 你做对了吗？