Perfluoroalkanes
全氟烃类
🗣️ 情景例句
Well, for one thing, he's my sister's boyfriend. Ann talks about Jack all the time.
首先，他是我妹妹的男朋友。安整天就是杰克长杰克短的。
Oh? Where were you?
哦，上哪儿去了？
How long have you lived here?
您在这里住了多长时间？