已知分子式为C12H12的有机物结构简式为,其苯环上的二溴代物有9种同分异构体,由此推断它的苯环上的四溴代物的同分异构体有[ ]
A.9种
B.10种
C.11种
D.12种
答案:A
I ____ talking to you. You never listen to me.
A.feed up with
B.feed on
C.am fed up with
D.am fed up of
简述化工技术经济的应用性特点。