happens
v. A1 Beginner US //ˈhæpənz// UK //hˈæpənz// hap·pens
v. to take place or occur, often by chance or without being planned. You use it to talk about events or situations that come into existence.
v. to take place or occur as an event or circumstance. Intransitive — it does not take a direct object and is frequently used with the dummy subject 'it'.
The accident happens very quickly.
The festival happens every summer in the park behind the library.
While the theory explains why the reaction occurs, it does not account for what happens when the temperature exceeds the safety threshold.
Usage
The verb is intransitive and cannot take a direct object.
Pitfall
The party was happened yesterdayThe party happened yesterdayThe verb 'happen' is intransitive and cannot be used in the passive voice.