Quadricovalent
四配价的
🗣️ 情景例句
Well, I ...
好啦， 我……
If you're not sure how to do is, ask me.
假如你拿不准怎样做，就来问我好了。
Oil rigs have to be repaired frequently and divers,who often have to work in darkness a hundred feet under water,
钻井平台需要经常修理，潜水员常常要在水面100英尺以下摸黑工作，