以下哪一味中药属麻醉中药( )
A．马钱子
B．川乌
C．罂粟壳
D．延胡索
E．雷公藤
参考答案：C
—You___________ stop me.
—Even if you __________it, I won't allow you to swim across the river.
A．mustn't; dare not do
B．may ; dare not do
C．can; dare to do
D．needn't; dare do
发电机的空气冷却器在什么情况下会结露？
