hot up

Từ điển Oxford Advanced Learner 8th

ˌhot ˈup derived
(BrE) (also ˌheat ˈup NAmE, BrE) (informal)to become more exciting or to show an increase in activity
•Things are really hotting up in the election campaign.
•The title race is certainly hotting up.
•The pace is hotting up.
Main entry: ↑hot_derived