I can grate you can grate he can grate we can grate you can grate they can grate
V-ing form
I can be grating you can be grating he can be grating we can be grating you can be grating they can be grating
Perfect
I can have grated you can have grated he can have grated we can have grated you can have grated they can have grated
V-ing perfect
I can have been grating you can have been grating he can have been grating we can have been grating you can have been grating they can have been grating
Negation
Simple form
I can't grate you can't grate he can't grate we can't grate you can't grate they can't grate
V-ing form
I can't be grating you can't be grating he can't be grating we can't be grating you can't be grating they can't be grating
Perfect
I can't have grated you can't have grated he can't have grated we can't have grated you can't have grated they can't have grated
V-ing perfect
I can't have been grating you can't have been grating he can't have been grating we can't have been grating you can't have been grating they can't have been grating
Interrogative form
Simple form
can I grate? can you grate? can he grate? can we grate? can you grate? can they grate?
V-ing form
can I be grating? can you be grating? can he be grating? can we be grating? can you be grating? can they be grating?
Perfect
can I have grated? can you have grated? can he have grated? can we have grated? can you have grated? can they have grated?
V-ing perfect
can I have been grating? can you have been grating? can he have been grating? can we have been grating? can you have been grating? can they have been grating?
Interro-negative form
Simple form
can't I grate? can't you grate? can't he grate? can't we grate? can't you grate? can't they grate?
V-ing form
can't I be grating? can't you be grating? can't he be grating? can't we be grating? can't you be grating? can't they be grating?
Perfect
can't I have grated? can't you have grated? can't he have grated? can't we have grated? can't you have grated? can't they have grated?
V-ing perfect
can't I have been grating? can't you have been grating? can't he have been grating? can't we have been grating? can't you have been grating? can't they have been grating?