I can grunt you can grunt she can grunt we can grunt you can grunt they can grunt
V-ing form
I can be grunting you can be grunting she can be grunting we can be grunting you can be grunting they can be grunting
Perfect
I can have grunted you can have grunted she 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 she can have been grunting we can have been grunting you can have been grunting they can have been grunting
Negation
Simple form
I cannot grunt you cannot grunt she cannot grunt we cannot grunt you cannot grunt they cannot grunt
V-ing form
I cannot be grunting you cannot be grunting she cannot be grunting we cannot be grunting you cannot be grunting they cannot be grunting
Perfect
I cannot have grunted you cannot have grunted she cannot have grunted we cannot have grunted you cannot have grunted they cannot have grunted
V-ing perfect
I cannot have been grunting you cannot have been grunting she cannot have been grunting we cannot have been grunting you cannot have been grunting they cannot have been grunting
Interrogative form
Simple form
can I grunt? can you grunt? can she grunt? can we grunt? can you grunt? can they grunt?
V-ing form
can I be grunting? can you be grunting? can she be grunting? can we be grunting? can you be grunting? can they be grunting?
Perfect
can I have grunted? can you have grunted? can she 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 she have been grunting? can we have been grunting? can you have been grunting? can they have been grunting?
Interro-negative form
Simple form
can I not grunt? can you not grunt? can she not grunt? can we not grunt? can you not grunt? can they not grunt?
V-ing form
can I not be grunting? can you not be grunting? can she not be grunting? can we not be grunting? can you not be grunting? can they not be grunting?
Perfect
can I not have grunted? can you not have grunted? can she not have grunted? can we not have grunted? can you not have grunted? can they not have grunted?
V-ing perfect
can I not have been grunting? can you not have been grunting? can she not have been grunting? can we not have been grunting? can you not have been grunting? can they not have been grunting?