I can refuse you can refuse he can refuse we can refuse you can refuse they can refuse
V-ing form
I can be refusing you can be refusing he can be refusing we can be refusing you can be refusing they can be refusing
Perfect
I can have refused you can have refused he can have refused we can have refused you can have refused they can have refused
V-ing perfect
I can have been refusing you can have been refusing he can have been refusing we can have been refusing you can have been refusing they can have been refusing
Negation
Simple form
I cannot refuse you cannot refuse he cannot refuse we cannot refuse you cannot refuse they cannot refuse
V-ing form
I cannot be refusing you cannot be refusing he cannot be refusing we cannot be refusing you cannot be refusing they cannot be refusing
Perfect
I cannot have refused you cannot have refused he cannot have refused we cannot have refused you cannot have refused they cannot have refused
V-ing perfect
I cannot have been refusing you cannot have been refusing he cannot have been refusing we cannot have been refusing you cannot have been refusing they cannot have been refusing
Interrogative form
Simple form
can I refuse? can you refuse? can he refuse? can we refuse? can you refuse? can they refuse?
V-ing form
can I be refusing? can you be refusing? can he be refusing? can we be refusing? can you be refusing? can they be refusing?
Perfect
can I have refused? can you have refused? can he have refused? can we have refused? can you have refused? can they have refused?
V-ing perfect
can I have been refusing? can you have been refusing? can he have been refusing? can we have been refusing? can you have been refusing? can they have been refusing?
Interro-negative form
Simple form
can I not refuse? can you not refuse? can he not refuse? can we not refuse? can you not refuse? can they not refuse?
V-ing form
can I not be refusing? can you not be refusing? can he not be refusing? can we not be refusing? can you not be refusing? can they not be refusing?
Perfect
can I not have refused? can you not have refused? can he not have refused? can we not have refused? can you not have refused? can they not have refused?
V-ing perfect
can I not have been refusing? can you not have been refusing? can he not have been refusing? can we not have been refusing? can you not have been refusing? can they not have been refusing?