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 can't refuse you can't refuse he can't refuse we can't refuse you can't refuse they can't refuse
V-ing form
I can't be refusing you can't be refusing he can't be refusing we can't be refusing you can't be refusing they can't be refusing
Perfect
I can't have refused you can't have refused he can't have refused we can't have refused you can't have refused they can't have refused
V-ing perfect
I can't have been refusing you can't have been refusing he can't have been refusing we can't have been refusing you can't have been refusing they can't 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't I refuse? can't you refuse? can't he refuse? can't we refuse? can't you refuse? can't they refuse?
V-ing form
can't I be refusing? can't you be refusing? can't he be refusing? can't we be refusing? can't you be refusing? can't they be refusing?
Perfect
can't I have refused? can't you have refused? can't he have refused? can't we have refused? can't you have refused? can't they have refused?
V-ing perfect
can't I have been refusing? can't you have been refusing? can't he have been refusing? can't we have been refusing? can't you have been refusing? can't they have been refusing?