Inis a preposition of time. It can be used with:“In” 作时间介词时，可与以下类型的词语搭配使用：
1 in + 月份
I'm going on holidayin May.
I'll next see you at Christmasin December.
I think we arrived some timeinJune.
2 in + 季节
Inwinter, it's cold.
I think this year I'll have my holidayin summer.
Mummy, do the leaves fall off the treein springorin autumn?
3 in + 年份
I finished schoolin2000.
The Titanic sankin1912.
I grew upin the 1930s.
4 in + 一天的上午、下午和晚上
I leave homein the morning.
I'll see youin the afternoon.
I get homein the evening.
Be careful!要注意！表示 “在夜里” 时，用介词 “at”。
I can't sleepatnight.
5 in + 过去、现在、将来
In the past, people died much younger.
You need to learn to livein the present.
In the future, you'll learn everything from videos. Profits from the farm were sometimes too small to meet operational expenses, let alone pay for a university degree.