at的最基本含义是“在（某一点）”，有些同学可能有点困惑，别急，还是结合语境，让我们逐个分析at这个词在牛津词典中的15种意思。
1、at the corner of the street；They arrived late at the airport.I met her at the hospital；How many people were there at the concert?可见，这时候at表示“在（某一地点）”，而且是具体的地点，可以让人找得到的那种地点。
2、He’s been at the bank longer than anyone else;She’s at shcool. 此时at表示“在（工作、学习的地点）”，但是注意区分，at school表示在学校这个地点，如I am at shcool，而in shcool表示在学校里学习，比如Students study in shcool。
3、We left at 2 o’clock；At night you can see the stars；What are you doing at the weekend?此时at表示“在（某一时间点或时刻）”
4、She got married at 25；He left school at the age of 16.此时at表示“在（人生的某一时间点）”
5、He pointed a gun at her；Somebody threw paint at the prime minister；What are you looking at?此时at表示“朝/向（某一个点）”，这个点通常是人或者某个东西。
6、He clutched wildly at the rope as he fell；She nibbled at a sandwich. 此时的at（用于动词后，涉及未做成或未做完的事）
7、Can you read a car number plate at fifty metres?此时at表示“在…远；从相隔…远的地方”，可以将其理解为“在（多远的一个点）”
8、The country is now at war；I think Mr Harris is at lunch；I felt at a disadvantage. 此时at表示的是“处于……状态”
9、He was driving at 70 mph；The noise came at two-minute intervals.此时at表示“在（某一速度点或者频率点、比率点）”
10、This was Henman at his best；The garden’s at its most beautiful in June.此时at表示“在（最好或者最差的那个点，或者说顶点或底点）”
11、I’m good at French；She’s hopeless at managing people. 此时at表示“在……方面”，但我更建议就理解为在“在（某一个能力点）”
12、They were impatient at the delay；She was delighted at the result. 此时at表示“（与形容词连用）因为，由于，对…”，这是at的引申义了，由某个点到某件事，即“在（某一件事）”
13、They attended the dinner at the chairman’s invitation. 此时at表示“应…（而）；响应；回答”，这也是约定俗成的用法了，直接记忆。
14、You can reach me at 637-2335, extension 354. 这是约定俗成的用法，此时at表示“在（某一号码）”
15、the symbol (@) used in email addresses. 这个@符号想必大家都不陌生，它就是at这个单词。
