—Why are you late?             

—My alarm clock didn't            .           [ ]

A. go off          

B. run off          

C. set off          

D. turn off

下列仪器使用时不允许用酒精灯加热的是 [ ]

A．容量瓶

B．蒸馏烧瓶

C．试管

D．烧杯