I can curl you can curl he can curl we can curl you can curl they can curl
V-ing form
I can be curling you can be curling he can be curling we can be curling you can be curling they can be curling
Perfect
I can have curled you can have curled he can have curled we can have curled you can have curled they can have curled
V-ing perfect
I can have been curling you can have been curling he can have been curling we can have been curling you can have been curling they can have been curling
Negation
Simple form
I cannot curl you cannot curl he cannot curl we cannot curl you cannot curl they cannot curl
V-ing form
I cannot be curling you cannot be curling he cannot be curling we cannot be curling you cannot be curling they cannot be curling
Perfect
I cannot have curled you cannot have curled he cannot have curled we cannot have curled you cannot have curled they cannot have curled
V-ing perfect
I cannot have been curling you cannot have been curling he cannot have been curling we cannot have been curling you cannot have been curling they cannot have been curling
Interrogative form
Simple form
can I curl? can you curl? can he curl? can we curl? can you curl? can they curl?
V-ing form
can I be curling? can you be curling? can he be curling? can we be curling? can you be curling? can they be curling?
Perfect
can I have curled? can you have curled? can he have curled? can we have curled? can you have curled? can they have curled?
V-ing perfect
can I have been curling? can you have been curling? can he have been curling? can we have been curling? can you have been curling? can they have been curling?
Interro-negative form
Simple form
can I not curl? can you not curl? can he not curl? can we not curl? can you not curl? can they not curl?
V-ing form
can I not be curling? can you not be curling? can he not be curling? can we not be curling? can you not be curling? can they not be curling?
Perfect
can I not have curled? can you not have curled? can he not have curled? can we not have curled? can you not have curled? can they not have curled?
V-ing perfect
can I not have been curling? can you not have been curling? can he not have been curling? can we not have been curling? can you not have been curling? can they not have been curling?