I.
noun
Happen is used after these nouns: ↑ break-in
II.
verb
ADVERB
▪ actually , really
▪
She couldn't quite believe that all this was actually ~ing to her.
▪ just
▪
I don't remember learning to swim, it just ~ed.
▪ never
▪ spontaneously
▪
Sometimes fun activities just ~ spontaneously; at other times they take careful planning.
▪ overnight , quickly
▪
Change doesn't ~ overnight.
▪ again
VERB + HAPPEN
▪ be going to
▪
They could only wait and see what was going to ~.
▪ be likely to
▪ be bound to
▪
Mistakes are bound to ~ sometimes.
▪ tend to
▪
What tends to ~ is that students spend the first week of the course in a blind panic, but settle down by the second or third week.
▪ want sth to
▪ make sth
▪
You have to make things ~ if you want them to happen.
▪ let sth
▪
Don't just sit back and let it ~.
PREPOSITION
▪ to
▪
She didn't know what was ~ing to her.
Happen is used with these nouns as the subject: ↑ abuse , ↑ accident , ↑ assault , ↑ attack , ↑ avalanche , ↑ breakthrough , ↑ burglary , ↑ catastrophe , ↑ change , ↑ coincidence , ↑ collision , ↑ crash , ↑ crime , ↑ deal , ↑ death , ↑ disaster , ↑ earthquake , ↑ emergency , ↑ eruption , ↑ event , ↑ evolution , ↑ explosion , ↑ fit , ↑ incident , ↑ injury , ↑ innovation , ↑ killing , ↑ leak , ↑ magic , ↑ meeting , ↑ merger , ↑ miracle , ↑ mistake , ↑ murder , ↑ phenomenon , ↑ riot , ↑ skirmish , ↑ smash , ↑ thing , ↑ tragedy , ↑ transformation