Regular verb: happen - happened - happened
Simple form | V-ing form |
- - it may happen - - - | - - it may be happening - - - |
Perfect | V-ing perfect |
- - it may have happened - - - | - - it may have been happening - - - |
Simple form | V-ing form |
- - it may not happen - - - | - - it may not be happening - - - |
Perfect | V-ing perfect |
- - it may not have happened - - - | - - it may not have been happening - - - |
Simple form | V-ing form |
- - may it happen? - - - | - - may it be happening? - - - |
Perfect | V-ing perfect |
- - may it have happened? - - - | - - may it have been happening? - - - |
Simple form | V-ing form |
- - may it not happen? - - - | - - may it not be happening? - - - |
Perfect | V-ing perfect |
- - may it not have happened? - - - | - - may it not have been happening? - - - |