铃响以前任何人均不得离开教室。
No one may leave the classroom until the bell goes.

他专心读报，连门铃也没听见。
He was too absorbed in the newspaper to hear the bell.

情况紧急时请按铃。
Ring the bell in an emergency.

电话铃响的时候我正在厨房里做饭。
I was cooking in the kitchen when the telephone rang.

他听到铃声响，就走过去开门。
He went to open the door when he heard the tinkle of the bell.

今天早晨，我被铃声唤醒。
I was roused by the sound of the bell this morning.

走廊的某处响起轻柔悦耳的铃声。
A musical bell softly sounded somewhere in the passageway.

听到铃声，我们赶快跑去上课。
Hearing the bell, we raced to the class.