清肺胃之热的药有()
A．白果
B．枇杷叶
C．马兜铃
D．葶苈子
E．以上均不是
参考答案：B
--- Why do you often take exercise? --- _____ me keep fit.
A．Help
B．Helping
C．To help
D．helped
发电机各绕组对外壳之间的绝缘电阻，一般应为（）以上。
A.100Mfl
B.150Mfl
C.200MC
D.250MQ
