汽车上所采用的刮水器有哪两类?
参考答案:
气动式和电动式
在额定频率和电压下,扶梯梯级沿运行方向空载时所测得的速度与额定速度之间的最大允许偏差为()%。
Last Sunday I had a good time _________ volleyball with my friend Alan. [ ]
A. play
B. to play
C. playing
D. played