I can refuse you can refuse she can refuse we can refuse you can refuse they can refuse
V-ing form
I can be refusing you can be refusing she can be refusing we can be refusing you can be refusing they can be refusing
Perfect
I can have refused you can have refused she 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 she 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 she cannot refuse we cannot refuse you cannot refuse they cannot refuse
V-ing form
I cannot be refusing you cannot be refusing she cannot be refusing we cannot be refusing you cannot be refusing they cannot be refusing
Perfect
I cannot have refused you cannot have refused she 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 she 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 she refuse? can we refuse? can you refuse? can they refuse?
V-ing form
can I be refusing? can you be refusing? can she be refusing? can we be refusing? can you be refusing? can they be refusing?
Perfect
can I have refused? can you have refused? can she 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 she 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 she 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 she 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 she 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 she not have been refusing? can we not have been refusing? can you not have been refusing? can they not have been refusing?