—Did you watch the basketball match?

—Oh, my alarm clock didn't  _________. When I woke up the match had been over.[ ]

A. go on              

B. go away

C. go up              

D. go off

分散控制系统的（）装臵或组件应采用完全独立的冗余配臵？

A.控制器

B.系统电源

C.通讯网络

D.为I/O模件供电的交流电源