架线电机车采用（）缓冲器。
A、铸钢的刚性
B、铸铁的刚性
C、弹性缓冲器
D、铰链缓冲器
参考答案：D
— Hello, may I have an appointment with the doctor?
— ___.
A．Sorry, he is busy at the moment.
B．Why didn’t you call earlier?
C．Certainly. May I know your name?
D．Sorry，he doesn’t want to see you.
保安项是摩托车大修质量的单项否决项，它包括（）、噪声、制动性能、灯光转向。
A.起动性
B.加速性
C.怠速污染物
D.滑行性
