Unsaturated compuond
[化] 不饱和化合物
🧩 词语组成解析
a. 没有饱和的, 不饱和的
🗣️ 情景例句
It's time we hired a secretary to answer the phones.
我们早就该请一个秘书接听电话了。
I invited him to come back, but he wouldn't.
我请他回来，但是他不肯。
I had a letter from my sister yesterday.
昨天我收到了姐姐的一封信，