could center
Regular verb: center - centered- centered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could center
you could center
he could center
we could center
you could center
they could center 	I could be centering
you could be centering
he could be centering
we could be centering
you could be centering
they could be centering	I could have centered
you could have centered
he could have centered
we could have centered
you could have centered
they could have centered	I could have been centering
you could have been centering
he could have been centering
we could have been centering
you could have been centering
they could have been centering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not center
you could not center
he could not center
we could not center
you could not center
they could not center 	I could not be centering
you could not be centering
he could not be centering
we could not be centering
you could not be centering
they could not be centering	I could not have centered
you could not have centered
he could not have centered
we could not have centered
you could not have centered
they could not have centered	I could not have been centering
you could not have been centering
he could not have been centering
we could not have been centering
you could not have been centering
they could not have been centering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I center?
could you center?
could he center?
could we center?
could you center?
could they center? 	could I be centering?
could you be centering?
could he be centering?
could we be centering?
could you be centering?
could they be centering? 	could I have centered?
could you have centered?
could he have centered?
could we have centered?
could you have centered?
could they have centered? 	could I have been centering?
could you have been centering?
could he have been centering?
could we have been centering?
could you have been centering?
could they have been centering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not center?
could you not center?
could he not center?
could we not center?
could you not center?
could they not center? 	could I not be centering?
could you not be centering?
could he not be centering?
could we not be centering?
could you not be centering?
could they not be centering? 	could I not have centered?
could you not have centered?
could he not have centered?
could we not have centered?
could you not have centered?
could they not have centered? 	could I not have been centering?
could you not have been centering?
could he not have been centering?
could we not have been centering?
could you not have been centering?
could they not have been centering?