I can bitter you can bitter he can bitter we can bitter you can bitter they can bitter
V-ing form
I can be bittering you can be bittering he can be bittering we can be bittering you can be bittering they can be bittering
Perfect
I can have bittered you can have bittered he can have bittered we can have bittered you can have bittered they can have bittered
V-ing perfect
I can have been bittering you can have been bittering he can have been bittering we can have been bittering you can have been bittering they can have been bittering
Negation
Simple form
I cannot bitter you cannot bitter he cannot bitter we cannot bitter you cannot bitter they cannot bitter
V-ing form
I cannot be bittering you cannot be bittering he cannot be bittering we cannot be bittering you cannot be bittering they cannot be bittering
Perfect
I cannot have bittered you cannot have bittered he cannot have bittered we cannot have bittered you cannot have bittered they cannot have bittered
V-ing perfect
I cannot have been bittering you cannot have been bittering he cannot have been bittering we cannot have been bittering you cannot have been bittering they cannot have been bittering
Interrogative form
Simple form
can I bitter? can you bitter? can he bitter? can we bitter? can you bitter? can they bitter?
V-ing form
can I be bittering? can you be bittering? can he be bittering? can we be bittering? can you be bittering? can they be bittering?
Perfect
can I have bittered? can you have bittered? can he have bittered? can we have bittered? can you have bittered? can they have bittered?
V-ing perfect
can I have been bittering? can you have been bittering? can he have been bittering? can we have been bittering? can you have been bittering? can they have been bittering?
Interro-negative form
Simple form
can I not bitter? can you not bitter? can he not bitter? can we not bitter? can you not bitter? can they not bitter?
V-ing form
can I not be bittering? can you not be bittering? can he not be bittering? can we not be bittering? can you not be bittering? can they not be bittering?
Perfect
can I not have bittered? can you not have bittered? can he not have bittered? can we not have bittered? can you not have bittered? can they not have bittered?
V-ing perfect
can I not have been bittering? can you not have been bittering? can he not have been bittering? can we not have been bittering? can you not have been bittering? can they not have been bittering?