could embitter
Regular verb: embitter - embittered- embittered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could embitter
you could embitter
he could embitter
we could embitter
you could embitter
they could embitter 	I could be embittering
you could be embittering
he could be embittering
we could be embittering
you could be embittering
they could be embittering	I could have embittered
you could have embittered
he could have embittered
we could have embittered
you could have embittered
they could have embittered	I could have been embittering
you could have been embittering
he could have been embittering
we could have been embittering
you could have been embittering
they could have been embittering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't embitter
you couldn't embitter
he couldn't embitter
we couldn't embitter
you couldn't embitter
they couldn't embitter 	I couldn't be embittering
you couldn't be embittering
he couldn't be embittering
we couldn't be embittering
you couldn't be embittering
they couldn't be embittering	I couldn't have embittered
you couldn't have embittered
he couldn't have embittered
we couldn't have embittered
you couldn't have embittered
they couldn't have embittered	I couldn't have been embittering
you couldn't have been embittering
he couldn't have been embittering
we couldn't have been embittering
you couldn't have been embittering
they couldn't have been embittering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I embitter?
could you embitter?
could he embitter?
could we embitter?
could you embitter?
could they embitter? 	could I be embittering?
could you be embittering?
could he be embittering?
could we be embittering?
could you be embittering?
could they be embittering? 	could I have embittered?
could you have embittered?
could he have embittered?
could we have embittered?
could you have embittered?
could they have embittered? 	could I have been embittering?
could you have been embittering?
could he have been embittering?
could we have been embittering?
could you have been embittering?
could they have been embittering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I embitter?
couldn't you embitter?
couldn't he embitter?
couldn't we embitter?
couldn't you embitter?
couldn't they embitter? 	couldn't I be embittering?
couldn't you be embittering?
couldn't he be embittering?
couldn't we be embittering?
couldn't you be embittering?
couldn't they be embittering? 	couldn't I have embittered?
couldn't you have embittered?
couldn't he have embittered?
couldn't we have embittered?
couldn't you have embittered?
couldn't they have embittered? 	couldn't I have been embittering?
couldn't you have been embittering?
couldn't he have been embittering?
couldn't we have been embittering?
couldn't you have been embittering?
couldn't they have been embittering?