1. In：一天的某個階段
I"ll come and see you in the morning for a cup of coffee, okay?
2. In：月份
We usually go camping in July or August.
3. In：年份
The house was built in 1835.
4. In：季節
The garden is wonderful in the spring when all the flowers come out.
5. In：長時間段
The population of Europe doubled in the nineteenth century.
6. In：時間持續長度，表示花了多長時間
He was such a clever musician. He could learn a song in about five minutes.
7. In a year"s time / in two month"s time，表示多長時間之後，某事會發生。
1. On：具體到某一天的日期
We moved into this house on 25 October 1987.
2. On：星期幾（單數）
I"ve got to go to London on Friday.
3. On：星期幾（複數），表示重複的事件
The office is closed on Fridays. (= every Friday)
4. On：特殊的日期
What do you normally do on your birthday
1. In：一天的某個階段
I"ll come and see you in the morning for a cup of coffee, okay?
2. In：月份
We usually go camping in July or August.
3. In：年份
The house was built in 1835.
4. In：季節
The garden is wonderful in the spring when all the flowers come out.
5. In：長時間段
The population of Europe doubled in the nineteenth century.
6. In：時間持續長度，表示花了多長時間
He was such a clever musician. He could learn a song in about five minutes.
7. In a year"s time / in two month"s time，表示多長時間之後，某事會發生。
1. On：具體到某一天的日期
We moved into this house on 25 October 1987.
2. On：星期幾（單數）
I"ve got to go to London on Friday.
3. On：星期幾（複數），表示重複的事件
The office is closed on Fridays. (= every Friday)
4. On：特殊的日期
What do you normally do on your birthday