could grimace
Regular verb: grimace - grimaced- grimaced

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could grimace
you could grimace
she could grimace
we could grimace
you could grimace
they could grimace 	I could be grimacing
you could be grimacing
she could be grimacing
we could be grimacing
you could be grimacing
they could be grimacing	I could have grimaced
you could have grimaced
she could have grimaced
we could have grimaced
you could have grimaced
they could have grimaced	I could have been grimacing
you could have been grimacing
she could have been grimacing
we could have been grimacing
you could have been grimacing
they could have been grimacing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't grimace
you couldn't grimace
she couldn't grimace
we couldn't grimace
you couldn't grimace
they couldn't grimace 	I couldn't be grimacing
you couldn't be grimacing
she couldn't be grimacing
we couldn't be grimacing
you couldn't be grimacing
they couldn't be grimacing	I couldn't have grimaced
you couldn't have grimaced
she couldn't have grimaced
we couldn't have grimaced
you couldn't have grimaced
they couldn't have grimaced	I couldn't have been grimacing
you couldn't have been grimacing
she couldn't have been grimacing
we couldn't have been grimacing
you couldn't have been grimacing
they couldn't have been grimacing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I grimace?
could you grimace?
could she grimace?
could we grimace?
could you grimace?
could they grimace? 	could I be grimacing?
could you be grimacing?
could she be grimacing?
could we be grimacing?
could you be grimacing?
could they be grimacing? 	could I have grimaced?
could you have grimaced?
could she have grimaced?
could we have grimaced?
could you have grimaced?
could they have grimaced? 	could I have been grimacing?
could you have been grimacing?
could she have been grimacing?
could we have been grimacing?
could you have been grimacing?
could they have been grimacing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I grimace?
couldn't you grimace?
couldn't she grimace?
couldn't we grimace?
couldn't you grimace?
couldn't they grimace? 	couldn't I be grimacing?
couldn't you be grimacing?
couldn't she be grimacing?
couldn't we be grimacing?
couldn't you be grimacing?
couldn't they be grimacing? 	couldn't I have grimaced?
couldn't you have grimaced?
couldn't she have grimaced?
couldn't we have grimaced?
couldn't you have grimaced?
couldn't they have grimaced? 	couldn't I have been grimacing?
couldn't you have been grimacing?
couldn't she have been grimacing?
couldn't we have been grimacing?
couldn't you have been grimacing?
couldn't they have been grimacing?