介词 “in” 除了有 “在……里面” 的意思，它还可以作时间介词，表示 “在……期间” 或 “在……（时间）之内”。
用法总结
In is 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 holiday in May.
- I'll next see you at Christmas in December.
- I think we arrived some time in June.
2. in + 季节
- In winter, it's cold.
- I think this year I'll have my holiday in summer.
- Mummy, do the leaves fall off the tree in spring or in autumn?
3. in + 年份
- I finished school in 2000.
- The Titanic sank in 1912.
- I grew up in the 1930s.
4. in + 一天的上午、下午和晚上
- I leave home in the morning.
- I'll see you in the afternoon.
- I get home in the evening.
Be careful!
要注意！表示 “在夜里” 时，用介词 “at”。
- I can't sleep at night.
5. in + 过去、现在、将来
- In the past, people died much younger.
- You need to learn to live in the present.
- In the future, you'll learn everything from videos.
