Cycloisomerisation
環(huán)異構(gòu)化
??? 情景例句
About three weeks. We'll have enough time for our talks.
大約三個禮拜，我們有足夠的時間交談了。
I'm giving you a gift.
我送給你一件禮物。
I'm not sure whether I have locked the door.
我沒把握是否鎖了門。