某化合物的化学式为C4H9Cl，它的可能的结构有几种
A．2
B．3
C．4
D．5
答案：C
f翻译重点词汇.
1. 星期二 n.__________ 2. Thursday n.__________
3. 星期三 n.__________ 4. Friday n.__________
5. 星期一 n.__________ 6. biology n.__________
The maritime radio system consisting of a series of coast stations transmitting coastal warnings is called（）.
A.NAVTEX
B.HYDROLANT/HYDROPAC
C.NAVAREA
D.SAFESEA
