go off
phrasal verb.to explode, make a loud noise, or stop being fresh. You use this when an alarm rings, a bomb explodes, or milk turns sour.
phrasal verb.to discharge or detonate; to emit a loud signal; or to undergo spoilage. This phrasal verb is intransitive in these senses and covers several distinct semantic fields including weaponry, electronics, and food safety.
“My alarm went off at six this morning.”
“The milk has gone off because someone left it out on the counter overnight.”
“Security forces evacuated the building immediately after the fire alarm went off, fearing that a suspicious package might also go off.”
used without a direct object; the subject is usually an alarm, a bomb, or food.
this is a highly polysemous phrasal verb; use a matching game to help students distinguish between the 'noise' sense and the 'spoiled food' sense.
this phrasal verb is intransitive and cannot be used in the passive voice.