I can caution you can caution she can caution we can caution you can caution they can caution
V-ing form
I can be cautioning you can be cautioning she can be cautioning we can be cautioning you can be cautioning they can be cautioning
Perfect
I can have cautioned you can have cautioned she can have cautioned we can have cautioned you can have cautioned they can have cautioned
V-ing perfect
I can have been cautioning you can have been cautioning she can have been cautioning we can have been cautioning you can have been cautioning they can have been cautioning
Negation
Simple form
I cannot caution you cannot caution she cannot caution we cannot caution you cannot caution they cannot caution
V-ing form
I cannot be cautioning you cannot be cautioning she cannot be cautioning we cannot be cautioning you cannot be cautioning they cannot be cautioning
Perfect
I cannot have cautioned you cannot have cautioned she cannot have cautioned we cannot have cautioned you cannot have cautioned they cannot have cautioned
V-ing perfect
I cannot have been cautioning you cannot have been cautioning she cannot have been cautioning we cannot have been cautioning you cannot have been cautioning they cannot have been cautioning
Interrogative form
Simple form
can I caution? can you caution? can she caution? can we caution? can you caution? can they caution?
V-ing form
can I be cautioning? can you be cautioning? can she be cautioning? can we be cautioning? can you be cautioning? can they be cautioning?
Perfect
can I have cautioned? can you have cautioned? can she have cautioned? can we have cautioned? can you have cautioned? can they have cautioned?
V-ing perfect
can I have been cautioning? can you have been cautioning? can she have been cautioning? can we have been cautioning? can you have been cautioning? can they have been cautioning?
Interro-negative form
Simple form
can I not caution? can you not caution? can she not caution? can we not caution? can you not caution? can they not caution?
V-ing form
can I not be cautioning? can you not be cautioning? can she not be cautioning? can we not be cautioning? can you not be cautioning? can they not be cautioning?
Perfect
can I not have cautioned? can you not have cautioned? can she not have cautioned? can we not have cautioned? can you not have cautioned? can they not have cautioned?
V-ing perfect
can I not have been cautioning? can you not have been cautioning? can she not have been cautioning? can we not have been cautioning? can you not have been cautioning? can they not have been cautioning?