on fire
1．burning着火；失火
We saw a house on fire when we passed the road．我们经过这条路时，看到一所房子失火了。
2．in a rage愤怒；急切
They were on fire with zeal to defend their native land．他们热血沸腾，决心捍卫自己的祖国。
He was on fire to rejoin his family after an absence of five years．他急切地想和阔别5年的家人团聚。