第 22 课 · 第 2 阶段: 常用词：代词、冠词、介词
时间介词：at / on / in
初级Prepositions of time: at / on / in
构成与用法
at 7 o'clock, on Monday, in the morning / in 2020 — 哪个介词搭配哪种时间
1.At, on, in——什么时候用哪个？
英语用三个不同的词表示时间：at 表示一个短暂、确切的时间点；on 用于某一天；in 用于较长的一段时间。
| 介词 | 用于 | 例子 |
|---|---|---|
| at | 钟点、确切的时刻 | at 7 o'clock, at 6:30, at noon, at midnight, at lunchtime, at sunset |
| on | 星期几、日期、特殊的日子 | on Monday, on 2 September, on my birthday, on New Year's Day |
| in | 一天中的某段时间、月份、季节、年份、年代、世纪 | in the morning, in July, in (the) summer, in 2020, in the 1990s, in the 21st century |
My English class starts at half past six.
我的英语课六点半开始。
My parents visit us on Sundays.
我父母每个星期天来看我们。
My grandparents got married in 1975.
我爷爷奶奶是 1975 年结婚的。
It's really hot in Saigon in April.
西贡四月份特别热。
记忆窍门：想象一个漏斗——in 最宽（年、月、季节），on 窄一些（某一天），at 最小（某一刻）。带月份的日期仍然是某一天，所以用 on：on 5 July，不是 in 5 July。
2.需要熟记的短语
- in the morning / in the afternoon / in the evening——但要说 at night。
- at the weekend（英式英语）= on the weekend（美式英语）。
- at Christmas, at Easter, at Tet（整个节日期间）——但 on Christmas Day, on New Year's Eve（特定的某一天）。
- at the moment（= 现在），at the same time（= 同时）。
- at the beginning of / at the end of the month——另见“On time / in time, at the end / in the end”一课。
- 日期：英式英语写作 on 5 July，美式英语写作 on July 5；口语中说 on the fifth of July 或 on July fifth。
My dad works at night and sleeps during the day.
我爸爸晚上上班，白天睡觉。
What are you doing at the weekend?
你周末打算做什么？
Families get together at Tet.
过春节时一家人会团聚。
Sorry, I'm busy at the moment.
抱歉，我现在正忙。
3.一天中的时段 + 具体某一天
单独说时是 in the morning，但提到具体某一天或日期时，要用 on：on Monday morning, on Friday evening, on the morning of 10 May。
I usually do yoga in the morning.
我通常早上做瑜伽。
Let's play badminton on Saturday morning.
我们星期六上午去打羽毛球吧。
Do you work on Sunday evenings?
你星期天晚上上班吗？
4.什么时候不用介词
在 next, last, this, every 前面，以及 today, tomorrow, yesterday, tonight 前面，都不用 at / on / in。
See you next Friday.
下周五见。（不说：on next Friday）
We went to Da Lat last summer.
我们去年夏天去了大叻。（不说：in last summer）
I go swimming every Thursday.
我每周四去游泳。
Are you free tomorrow afternoon?
你明天下午有空吗？
在非正式口语中，尤其是美式英语，人们常省略星期几前面的 on：See you Friday. = See you on Friday. 两种说法都对；拿不准的话，就保留 on。
5.In + 一段时间：从现在算起多久以后
In + 一段时间还可以表示“从现在算起，过了这么长时间以后”：in ten minutes, in two weeks, in a moment。它也可以表示做某事花了多长时间。
The bus will be here in five minutes.
公交车五分钟后到。（不说：after five minutes）
My cousin is getting married in two months.
我表姐两个月后结婚。
He learned to ride a bike in one day.
他一天就学会了骑自行车。（表示花了多长时间）
6.常见错误
I study best at the morning.I study best in the morning.
一天中的时段用 in（at night 除外）。
My sister's wedding is on October.My sister's wedding is in October.
月份用 in。
The concert is in 20 May.The concert is on 20 May.
具体的日期用 on。
We have a meeting on next Monday.We have a meeting next Monday.
next / last / this / every 前面不用介词。
The train leaves in 8:15.The train leaves at 8:15.
钟点用 at。
I'll call you after ten minutes.I'll call you in ten minutes.
“从现在算起多久以后”用 in。
例句
- The film starts at 8 o'clock.
- My birthday is in July.
- We moved to Da Nang in 2019.
- The shop closes at midnight.
