A.has happened
B.has been happened
C.was happened
D.happened
A.brought
B.led to
C.happened
D.came
A.happened
B.participated
C.involved
D.joined
A.postpone
B.postcard
C.propose
D.surround
A.happen on
B.happen to
C.happened to
D.happen upon
A.happens
B.which is happening
C.which happening
D.which happened
It () that I met one of my old classmates on my way home yesterday.
A.took place
B.occurred
C.broke out
D.happened
A.happened / have waited
B.will happen / am waiting
C.has happened / have been waiting
D.was happened / have waited
A.has happened
B. was happened
C.happened
D.was happening