既有解表作用，又有明目作用的药物是（）
A.柴胡、薄荷
B.桑叶、菊花
C.柴胡、蔓荆子
D.葛根、蝉衣
E.以上都不是
参考答案：B
绕线型电动机转子串入频敏电阻器起动的原理是什么？
Why did Tom go to school on foot [A] Because he didn’t catch the bus. [B] Because he got up very early. [C] Because he wanted to do exercises.
