in
國小小三上/ɪn/
prep.在…裡面
inside something, or during a period of time
什麼時候用
時間由大到小：in（年、月、季節）→ on（日期、星期）→ at（幾點）。
常見錯誤
- in Monday ✗ → on Monday ✓
- in 3 o'clock ✗ → at 3 o'clock ✓
常見搭配
- in the morning
- in 2026
- in English
例句
The keys are in the bag.
鑰匙在包包裡。
We met in July.
我們七月認識的。