1 to explode 爆炸: A bomb has gone off in the city centre. 有枚炸弹在市中心爆炸了。

2 to make a sudden loud noise 突然发出大响声: I woke up when my alarm clock went off. 闹钟一响我就醒了。

3 (used about lights, heating, etc) to stop working （指灯、暖气等）失灵: There was a power cut and all the lights went off. 停电了，所有灯都熄灭了。

4 (used about food and drink) to become too old to eat or drink; to go bad （指食物、饮料）变质

5 to become worse in quality 品质变差: I used to like that band but they've gone off recently. 我过去很喜欢那支乐队，可是他们近来退步了。