“Well done, John! Not a single mistake____in your exam paper this time!”said the teacher．

A．you made

B．did you make

C．had you made

D．you have made

若交换设备出现了故障，则采用中断的方式中断正在执行的（）程序，优先执行故障处理程序。

A.周期

B.基本级

C.信号处理

D.周期或基本级