Acetals
缩醛
🗣️ 情景例句
Look before you leap.
三思而后行。
Don't mention it. I hope you can come again soon.
不用谢，希望你不久能再来。
He sent the journalist two more faxes, but received no reply.
他给记者先后发去两份传真，但对方毫无反应。