抽搐持续状态的处理，错误的是（）。
A.尽快找出病因
B.吸氧
C.禁用甘露醇
D.首选地西泮止惊
E.积极降温
参考答案：C
Bob's lectures _____ a fairly wide range and I can't sum up what he says in a few sentences. [ ]
A. covered
B. conveyed
C. considered
D. commanded
如图是一个透明圆柱介质的横截面，B、C为圆上两点。一束单色光沿AB方向入射，从c点射出，已知∠ABO＝∠BOC=1200，真空中光速c=3×108m/s。求：
①光在介质中的折射率n
②光在介质中传播速度v
