I can fitter you can fitter he can fitter we can fitter you can fitter they can fitter
V-ing form
I can be fittering you can be fittering he can be fittering we can be fittering you can be fittering they can be fittering
Perfect
I can have fittered you can have fittered he can have fittered we can have fittered you can have fittered they can have fittered
V-ing perfect
I can have been fittering you can have been fittering he can have been fittering we can have been fittering you can have been fittering they can have been fittering
Negation
Simple form
I cannot fitter you cannot fitter he cannot fitter we cannot fitter you cannot fitter they cannot fitter
V-ing form
I cannot be fittering you cannot be fittering he cannot be fittering we cannot be fittering you cannot be fittering they cannot be fittering
Perfect
I cannot have fittered you cannot have fittered he cannot have fittered we cannot have fittered you cannot have fittered they cannot have fittered
V-ing perfect
I cannot have been fittering you cannot have been fittering he cannot have been fittering we cannot have been fittering you cannot have been fittering they cannot have been fittering
Interrogative form
Simple form
can I fitter? can you fitter? can he fitter? can we fitter? can you fitter? can they fitter?
V-ing form
can I be fittering? can you be fittering? can he be fittering? can we be fittering? can you be fittering? can they be fittering?
Perfect
can I have fittered? can you have fittered? can he have fittered? can we have fittered? can you have fittered? can they have fittered?
V-ing perfect
can I have been fittering? can you have been fittering? can he have been fittering? can we have been fittering? can you have been fittering? can they have been fittering?
Interro-negative form
Simple form
can I not fitter? can you not fitter? can he not fitter? can we not fitter? can you not fitter? can they not fitter?
V-ing form
can I not be fittering? can you not be fittering? can he not be fittering? can we not be fittering? can you not be fittering? can they not be fittering?
Perfect
can I not have fittered? can you not have fittered? can he not have fittered? can we not have fittered? can you not have fittered? can they not have fittered?
V-ing perfect
can I not have been fittering? can you not have been fittering? can he not have been fittering? can we not have been fittering? can you not have been fittering? can they not have been fittering?