根据时间继电器触点的延时通断情况，它的延时触点共有（）种形式。
A.1
B.2
C.3
D.4
参考答案：D
—Shall we go skating or stay at home?
—Which ___ do yourself? [ ]
A. do you rather
B. would you rather
C. will you rather
D. should you rather
一台多媒体PC机具有图像输入功能，为输入照片图像所采用的外部设备是 ( )。
A．鼠标
B．扫描仪
C．数字化仪
D．键盘
skating or stay at home?