Ectosac
[医] 外膜, 外囊(卵)
🗣️ 情景例句
There are several tours of the Grand Canyon.
到大峡谷有好几个旅游团。
Please come in; you're right on time.
请进，你正好准时到来。
How often do you write?
你们隔多久写信？