could greaten
Regular verb: greaten - greatened- greatened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could greaten
you could greaten
he could greaten
we could greaten
you could greaten
they could greaten 	I could be greatening
you could be greatening
he could be greatening
we could be greatening
you could be greatening
they could be greatening	I could have greatened
you could have greatened
he could have greatened
we could have greatened
you could have greatened
they could have greatened	I could have been greatening
you could have been greatening
he could have been greatening
we could have been greatening
you could have been greatening
they could have been greatening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't greaten
you couldn't greaten
he couldn't greaten
we couldn't greaten
you couldn't greaten
they couldn't greaten 	I couldn't be greatening
you couldn't be greatening
he couldn't be greatening
we couldn't be greatening
you couldn't be greatening
they couldn't be greatening	I couldn't have greatened
you couldn't have greatened
he couldn't have greatened
we couldn't have greatened
you couldn't have greatened
they couldn't have greatened	I couldn't have been greatening
you couldn't have been greatening
he couldn't have been greatening
we couldn't have been greatening
you couldn't have been greatening
they couldn't have been greatening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I greaten?
could you greaten?
could he greaten?
could we greaten?
could you greaten?
could they greaten? 	could I be greatening?
could you be greatening?
could he be greatening?
could we be greatening?
could you be greatening?
could they be greatening? 	could I have greatened?
could you have greatened?
could he have greatened?
could we have greatened?
could you have greatened?
could they have greatened? 	could I have been greatening?
could you have been greatening?
could he have been greatening?
could we have been greatening?
could you have been greatening?
could they have been greatening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I greaten?
couldn't you greaten?
couldn't he greaten?
couldn't we greaten?
couldn't you greaten?
couldn't they greaten? 	couldn't I be greatening?
couldn't you be greatening?
couldn't he be greatening?
couldn't we be greatening?
couldn't you be greatening?
couldn't they be greatening? 	couldn't I have greatened?
couldn't you have greatened?
couldn't he have greatened?
couldn't we have greatened?
couldn't you have greatened?
couldn't they have greatened? 	couldn't I have been greatening?
couldn't you have been greatening?
couldn't he have been greatening?
couldn't we have been greatening?
couldn't you have been greatening?
couldn't they have been greatening?