处理痤疮时被感染属于（）感染。
A.接触
B.创伤
C.媒介
D.呼吸
参考答案：B
Sitting in a car which stops suddenly, you feel that you are ______
A．at rest
B．left behind
C．jerked forward
D．jerked backwards
电机车运输信号系统是如何分类的？
