B1 起火，着火
If something is on fire, it is burning when it should not be.
If your home was on fire and you could save only one thing, what would it be? 如果你家着了火，而你只能抢救出一样东西，你会拿什么呢？
The field behind the house was on fire.
Bombs were falling and the city was on fire.
There were reports of cars on fire in many of the streets.
He ran to tell us that the barn was on fire.
Synonyms: ablazeaflame alight (BURNING)
See also: fire noun (FLAMES)