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 couldn't behave you couldn't behave she couldn't behave we couldn't behave you couldn't behave they couldn't behave
V-ing form
I couldn't be behaving you couldn't be behaving she couldn't be behaving we couldn't be behaving you couldn't be behaving they couldn't be behaving
Perfect
I couldn't have behaved you couldn't have behaved she couldn't have behaved we couldn't have behaved you couldn't have behaved they couldn't have behaved
V-ing perfect
I couldn't have been behaving you couldn't have been behaving she couldn't have been behaving we couldn't have been behaving you couldn't have been behaving they couldn't 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
couldn't I behave? couldn't you behave? couldn't she behave? couldn't we behave? couldn't you behave? couldn't they behave?
V-ing form
couldn't I be behaving? couldn't you be behaving? couldn't she be behaving? couldn't we be behaving? couldn't you be behaving? couldn't they be behaving?
Perfect
couldn't I have behaved? couldn't you have behaved? couldn't she have behaved? couldn't we have behaved? couldn't you have behaved? couldn't they have behaved?
V-ing perfect
couldn't I have been behaving? couldn't you have been behaving? couldn't she have been behaving? couldn't we have been behaving? couldn't you have been behaving? couldn't they have been behaving?