I can ask you can ask he can ask we can ask you can ask they can ask
V-ing form
I can be asking you can be asking he can be asking we can be asking you can be asking they can be asking
Perfect
I can have asked you can have asked he can have asked we can have asked you can have asked they can have asked
V-ing perfect
I can have been asking you can have been asking he can have been asking we can have been asking you can have been asking they can have been asking
Negation
Simple form
I can't ask you can't ask he can't ask we can't ask you can't ask they can't ask
V-ing form
I can't be asking you can't be asking he can't be asking we can't be asking you can't be asking they can't be asking
Perfect
I can't have asked you can't have asked he can't have asked we can't have asked you can't have asked they can't have asked
V-ing perfect
I can't have been asking you can't have been asking he can't have been asking we can't have been asking you can't have been asking they can't have been asking
Interrogative form
Simple form
can I ask? can you ask? can he ask? can we ask? can you ask? can they ask?
V-ing form
can I be asking? can you be asking? can he be asking? can we be asking? can you be asking? can they be asking?
Perfect
can I have asked? can you have asked? can he have asked? can we have asked? can you have asked? can they have asked?
V-ing perfect
can I have been asking? can you have been asking? can he have been asking? can we have been asking? can you have been asking? can they have been asking?
Interro-negative form
Simple form
can't I ask? can't you ask? can't he ask? can't we ask? can't you ask? can't they ask?
V-ing form
can't I be asking? can't you be asking? can't he be asking? can't we be asking? can't you be asking? can't they be asking?
Perfect
can't I have asked? can't you have asked? can't he have asked? can't we have asked? can't you have asked? can't they have asked?
V-ing perfect
can't I have been asking? can't you have been asking? can't he have been asking? can't we have been asking? can't you have been asking? can't they have been asking?