English verb conjugation MAY HAPPEN
Regular verb: happen - happened - happened
Affirmation
Simple form
--
it may happen
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V-ing form
--
it may be happening
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Perfect
--
it may have happened
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V-ing perfect
--
it may have been happening
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Negation
Simple form
--
it may not happen
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V-ing form
--
it may not be happening
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Perfect
--
it may not have happened
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V-ing perfect
--
it may not have been happening
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Interrogative form
Simple form
--
may it happen?
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V-ing form
--
may it be happening?
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Perfect
--
may it have happened?
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V-ing perfect
--
may it have been happening?
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Interro-negative form
Simple form
--
may it not happen?
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V-ing form
--
may it not be happening?
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Perfect
--
may it not have happened?
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V-ing perfect
--
may it not have been happening?
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