Op. cit.
abbr. 前面引用的书(in the work already quoted)
🗣️ 情景例句
What do you recommend today?
今天你推荐什么沙拉？
Art is long, but lift is short.
人生有涯，而学无涯。
This time, the policeman lost his temper.
这一次警察火了。