could decelerate
Regular verb: decelerate - decelerated- decelerated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could decelerate
you could decelerate
she could decelerate
we could decelerate
you could decelerate
they could decelerate 	I could be decelerating
you could be decelerating
she could be decelerating
we could be decelerating
you could be decelerating
they could be decelerating	I could have decelerated
you could have decelerated
she could have decelerated
we could have decelerated
you could have decelerated
they could have decelerated	I could have been decelerating
you could have been decelerating
she could have been decelerating
we could have been decelerating
you could have been decelerating
they could have been decelerating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not decelerate
you could not decelerate
she could not decelerate
we could not decelerate
you could not decelerate
they could not decelerate 	I could not be decelerating
you could not be decelerating
she could not be decelerating
we could not be decelerating
you could not be decelerating
they could not be decelerating	I could not have decelerated
you could not have decelerated
she could not have decelerated
we could not have decelerated
you could not have decelerated
they could not have decelerated	I could not have been decelerating
you could not have been decelerating
she could not have been decelerating
we could not have been decelerating
you could not have been decelerating
they could not have been decelerating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I decelerate?
could you decelerate?
could she decelerate?
could we decelerate?
could you decelerate?
could they decelerate? 	could I be decelerating?
could you be decelerating?
could she be decelerating?
could we be decelerating?
could you be decelerating?
could they be decelerating? 	could I have decelerated?
could you have decelerated?
could she have decelerated?
could we have decelerated?
could you have decelerated?
could they have decelerated? 	could I have been decelerating?
could you have been decelerating?
could she have been decelerating?
could we have been decelerating?
could you have been decelerating?
could they have been decelerating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not decelerate?
could you not decelerate?
could she not decelerate?
could we not decelerate?
could you not decelerate?
could they not decelerate? 	could I not be decelerating?
could you not be decelerating?
could she not be decelerating?
could we not be decelerating?
could you not be decelerating?
could they not be decelerating? 	could I not have decelerated?
could you not have decelerated?
could she not have decelerated?
could we not have decelerated?
could you not have decelerated?
could they not have decelerated? 	could I not have been decelerating?
could you not have been decelerating?
could she not have been decelerating?
could we not have been decelerating?
could you not have been decelerating?
could they not have been decelerating?