Polyacetylen
聚乙炔; 聚乙炔
??? 情景例句
Would you like something to drink?
你們要點什么飲料嗎？
She's very well,thank you.
她很好，謝謝您。
Needless to say, the bigger the risk an insurance company takes, the higher the premium you will have to pay.
不用說，保險公司承擔風險越大，你付的保險費也就越高。