The alarm_______ when the thieves went into the office.

A．went away

B．went along

C．went by

D．went off

产生的灭火泡沫倍数在20～200的泡沫灭火系统为（）。

A.低倍数泡沫灭火系统

B.中倍数泡沫灭火系统

C.高倍数泡沫灭火系统

D.超高倍数泡沫灭火系统