I can grunt you can grunt he can grunt we can grunt you can grunt they can grunt
V-ing form
I can be grunting you can be grunting he can be grunting we can be grunting you can be grunting they can be grunting
Perfect
I can have grunted you can have grunted he can have grunted we can have grunted you can have grunted they can have grunted
V-ing perfect
I can have been grunting you can have been grunting he can have been grunting we can have been grunting you can have been grunting they can have been grunting
Negation
Simple form
I can't grunt you can't grunt he can't grunt we can't grunt you can't grunt they can't grunt
V-ing form
I can't be grunting you can't be grunting he can't be grunting we can't be grunting you can't be grunting they can't be grunting
Perfect
I can't have grunted you can't have grunted he can't have grunted we can't have grunted you can't have grunted they can't have grunted
V-ing perfect
I can't have been grunting you can't have been grunting he can't have been grunting we can't have been grunting you can't have been grunting they can't have been grunting
Interrogative form
Simple form
can I grunt? can you grunt? can he grunt? can we grunt? can you grunt? can they grunt?
V-ing form
can I be grunting? can you be grunting? can he be grunting? can we be grunting? can you be grunting? can they be grunting?
Perfect
can I have grunted? can you have grunted? can he have grunted? can we have grunted? can you have grunted? can they have grunted?
V-ing perfect
can I have been grunting? can you have been grunting? can he have been grunting? can we have been grunting? can you have been grunting? can they have been grunting?
Interro-negative form
Simple form
can't I grunt? can't you grunt? can't he grunt? can't we grunt? can't you grunt? can't they grunt?
V-ing form
can't I be grunting? can't you be grunting? can't he be grunting? can't we be grunting? can't you be grunting? can't they be grunting?
Perfect
can't I have grunted? can't you have grunted? can't he have grunted? can't we have grunted? can't you have grunted? can't they have grunted?
V-ing perfect
can't I have been grunting? can't you have been grunting? can't he have been grunting? can't we have been grunting? can't you have been grunting? can't they have been grunting?