Op. cit.
abbr. 前面引用的书(in the work already quoted)
🗣️ 情景例句
Mm-hmm. Let's go ...
嗯哼。我们走吧……
That house is for sale.It has central heating.
那幢房子是待售的，它有中央暖气系统。
Yes, that's right.
是的。