at

      在（某处）used to say where sth/sb is or where sth happens

      在（表示学习或工作地点）used to say where sb works or studies

      在（某时间或时刻）used to say when sth happens

      在…岁时used to state the age at which sb does sth

      向；朝in the direction of or towards sb/sth

      （用于动词后，涉及未做成或未做完的事）used after a verb to show that sb tries to do sth, or partly does sth, but does not succeed or complete it

      在…远；从相隔…远的地方used to state the distance away from sth

      处于…状态used to show the situation sb/sth is in, what sb is doing or what is happening

      （用于速度、比率等）以，达used to show a rate, speed, etc.

      ~ sb's/sth's best/worst, etc.

      处于最佳（或最差等）状态；在全盛（或谷底等）时期used to say that sb/sth is as good, bad, etc. as they can be

      （与形容词连用，表示能力）在…方面used with adjectives to show how well sb does sth

      （与形容词连用）因为，由于，对…used with adjectives to show the cause of sth

      应…（而）；响应；回答in response to sth

      （提供电话号码时用）used when giving a telephone number

      （用于电子邮箱地址中的符号 @）the symbol ( @ ) used in email addresses