Perfluoroethylene
[机] 四氟乙烯
🗣️ 情景例句
I am sorry. I am not free right now.
对不起，我现在很忙。
The doctor said I looked anemic.
医生说我看起来贫血。
Why do you keep asking me the same question?
你怎么又问我同样的问题？