English verb conjugation MAY HAPPEN

Regular verb: happen - happened - happened

Affirmation

Simple form

-
-
it may happen
-
-
-

V-ing form

-
-
it may be happening
-
-
-

Perfect

-
-
it may have happened
-
-
-

V-ing perfect

-
-
it may have been happening
-
-
-

Simple form

-
-
it may not happen
-
-
-

V-ing form

-
-
it may not be happening
-
-
-

Perfect

-
-
it may not have happened
-
-
-

V-ing perfect

-
-
it may not have been happening
-
-
-

Simple form

-
-
may it happen?
-
-
-

V-ing form

-
-
may it be happening?
-
-
-

Perfect

-
-
may it have happened?
-
-
-

V-ing perfect

-
-
may it have been happening?
-
-
-

Simple form

-
-
may it not happen?
-
-
-

V-ing form

-
-
may it not be happening?
-
-
-

Perfect

-
-
may it not have happened?
-
-
-

V-ing perfect

-
-
may it not have been happening?
-
-
-