I can rat you can rat she can rat we can rat you can rat they can rat
V-ing form
I can be ratting you can be ratting she can be ratting we can be ratting you can be ratting they can be ratting
Perfect
I can have ratted you can have ratted she can have ratted we can have ratted you can have ratted they can have ratted
V-ing perfect
I can have been ratting you can have been ratting she can have been ratting we can have been ratting you can have been ratting they can have been ratting
Negation
Simple form
I cannot rat you cannot rat she cannot rat we cannot rat you cannot rat they cannot rat
V-ing form
I cannot be ratting you cannot be ratting she cannot be ratting we cannot be ratting you cannot be ratting they cannot be ratting
Perfect
I cannot have ratted you cannot have ratted she cannot have ratted we cannot have ratted you cannot have ratted they cannot have ratted
V-ing perfect
I cannot have been ratting you cannot have been ratting she cannot have been ratting we cannot have been ratting you cannot have been ratting they cannot have been ratting
Interrogative form
Simple form
can I rat? can you rat? can she rat? can we rat? can you rat? can they rat?
V-ing form
can I be ratting? can you be ratting? can she be ratting? can we be ratting? can you be ratting? can they be ratting?
Perfect
can I have ratted? can you have ratted? can she have ratted? can we have ratted? can you have ratted? can they have ratted?
V-ing perfect
can I have been ratting? can you have been ratting? can she have been ratting? can we have been ratting? can you have been ratting? can they have been ratting?
Interro-negative form
Simple form
can I not rat? can you not rat? can she not rat? can we not rat? can you not rat? can they not rat?
V-ing form
can I not be ratting? can you not be ratting? can she not be ratting? can we not be ratting? can you not be ratting? can they not be ratting?
Perfect
can I not have ratted? can you not have ratted? can she not have ratted? can we not have ratted? can you not have ratted? can they not have ratted?
V-ing perfect
can I not have been ratting? can you not have been ratting? can she not have been ratting? can we not have been ratting? can you not have been ratting? can they not have been ratting?