Polyacetylen
聚乙炔; 聚乙炔
🗣️ 情景例句
My visa is multi-entry; it allows me to exit the country and then re-enter, as ofter as I like.
我的签证是往返签证，我可以随便进出这个国家。
What sort of medicine do you take?
你吃的是什么药？
The deepest holes of all are made for oil, and they go down to as much as 25,000 feet.
在所有洞穴中，为寻找石油所钻的洞是最深的，这些洞可深达25，000英尺。