视网膜血管炎主要病变发生在（）
A.黄斑部
B.周边部
C.赤道部
D.视盘周围
E.以上都不对
参考答案：B
I didn't understand ______, so I raised my hand to ask for help. [ ]
A. what my teacher says
B. what does my teacher say
C. what my teacher said
D. what did my teacher say
核衣壳是病毒粒子的主要结构，核衣壳由哪些成分组成的（）
A.衣壳和囊膜
B.核酸和囊膜
C.衣壳和核心
D.核酸和包膜
E.囊膜和核酸
