Epimerization
差向[立体]异构(作用)
🗣️ 情景例句
Does the hotel have a tour service?
这宾馆有旅游服务吗？
Nothing so bad, as not to be good for something.
塞翁失马，安知非福。
Do you want to have lunch with us?
你跟我们一起吃午饭好吗？