1. at后可接：
(1) 一天之内的某个时间(在早上，在下午，在晚上除外）：at daybreak/noon/night/midnight/...
(2) 时刻：at ...o’clock/six thirty/ten to ten/a quarter past five/...
(3) 年龄：at the age of five/5 years old/twenty-four...
(4) 某个节日（指的是节日期间）： at Christmas /the Spring Festival/Mid-Autumn Festival/Halloween...
2. in后可接：
(1) 大于一天的时间: in the ninth week/January/winter/1993/...
(2) 在上午，下午或晚上（泛指）：in the morning/the afternoon/the evening
3. on后可接：
(1) 具体到哪一天的时间：on Sunday/May 4th/...
(2) 某个节日（指的是节日当天）：on Christmas Day/National Day/Chinese New Year’s Eve/Halloween Day...
(3) 特定的一天之中的某个时间：on Sunday evening/a cold winter morning/a rainy night/ the noon of the same day...
【练习】.
1. ______1999 in
2. _______9:45 at
3. _______the evening in
4. _______Monday evening on
5. ________June in
6. ________the afternoon in
7. _______noon at
8. ______night at
9. ______Children’s Day on
10. ______Teachers’ Day on
11. _______8 o’clock at
12. _______Summer in
13. _______May in
14. ______May, 1999 in
15. ________May 15th,1999 on
