Verbo regular: happen - happened - happened
Forma simple | Forma com V-ing |
- - it could happen - - - | - - it could be happening - - - |
Perfeito | Perfeito com V-ing |
- - it could have happened - - - | - - it could have been happening - - - |
Forma simple | Forma com V-ing |
- - it could not happen - - - | - - it could not be happening - - - |
Perfeito | Perfeito com V-ing |
- - it could not have happened - - - | - - it could not have been happening - - - |
Forma simple | Forma com V-ing |
- - could it happen? - - - | - - could it be happening? - - - |
Perfeito | Perfeito com V-ing |
- - could it have happened? - - - | - - could it have been happening? - - - |
Forma simple | Forma com V-ing |
- - could it not happen? - - - | - - could it not be happening? - - - |
Perfeito | Perfeito com V-ing |
- - could it not have happened? - - - | - - could it not have been happening? - - - |