could behave
Regular verb: behave - behaved- behaved

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could behave
you could behave
she could behave
we could behave
you could behave
they could behave 	I could be behaving
you could be behaving
she could be behaving
we could be behaving
you could be behaving
they could be behaving	I could have behaved
you could have behaved
she could have behaved
we could have behaved
you could have behaved
they could have behaved	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 	V-ing form 	Perfect 	V-ing perfect 	
I could not behave
you could not behave
she could not behave
we could not behave
you could not behave
they could not behave 	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	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	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 	V-ing form 	Perfect 	V-ing perfect 	
could I behave?
could you behave?
could she behave?
could we behave?
could you behave?
could they behave? 	could I be behaving?
could you be behaving?
could she be behaving?
could we be behaving?
could you be behaving?
could they be behaving? 	could I have behaved?
could you have behaved?
could she have behaved?
could we have behaved?
could you have behaved?
could they have behaved? 	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 	V-ing form 	Perfect 	V-ing perfect 	
could I not behave?
could you not behave?
could she not behave?
could we not behave?
could you not behave?
could they not behave? 	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? 	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? 	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?