I could behave you could behave she could behave we could behave you could behave they could behave
V-ing form
I could be behaving you could be behaving she could be behaving we could be behaving you could be behaving they could be behaving
Perfect
I could have behaved you could have behaved she could have behaved we could have behaved you could have behaved they could have behaved
V-ing perfect
I could have been behaving you could have been behaving she could have been behaving we could have been behaving you could have been behaving they could have been behaving
Negation
Simple form
I could not behave you could not behave she could not behave we could not behave you could not behave they could not behave
V-ing form
I could not be behaving you could not be behaving she could not be behaving we could not be behaving you could not be behaving they could not be behaving
Perfect
I could not have behaved you could not have behaved she could not have behaved we could not have behaved you could not have behaved they could not have behaved
V-ing perfect
I could not have been behaving you could not have been behaving she could not have been behaving we could not have been behaving you could not have been behaving they could not have been behaving
Interrogative form
Simple form
could I behave? could you behave? could she behave? could we behave? could you behave? could they behave?
V-ing form
could I be behaving? could you be behaving? could she be behaving? could we be behaving? could you be behaving? could they be behaving?
Perfect
could I have behaved? could you have behaved? could she have behaved? could we have behaved? could you have behaved? could they have behaved?
V-ing perfect
could I have been behaving? could you have been behaving? could she have been behaving? could we have been behaving? could you have been behaving? could they have been behaving?
Interro-negative form
Simple form
could I not behave? could you not behave? could she not behave? could we not behave? could you not behave? could they not behave?
V-ing form
could I not be behaving? could you not be behaving? could she not be behaving? could we not be behaving? could you not be behaving? could they not be behaving?
Perfect
could I not have behaved? could you not have behaved? could she not have behaved? could we not have behaved? could you not have behaved? could they not have behaved?
V-ing perfect
could I not have been behaving? could you not have been behaving? could she not have been behaving? could we not have been behaving? could you not have been behaving? could they not have been behaving?