可编程序控制器对中断的响应是（）后进行
A、指令执行结束后
B、扫描周期内某一个任务完成
C、直接进行
D、延时1微秒
参考答案：B
常用抗青光眼手术？
— Turn off the TV, Jack. ____ your homework now?
— Mum, just ten more minutes, please.
A．Should you be doing
B．Shouldn’t you be doing
C．Couldn’t you be doing
D．Will you be doing
— Turn off the TV, Jack. ____ your homework now?