could retard
Regular verb: retard - retarded- retarded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could retard
you could retard
she could retard
we could retard
you could retard
they could retard 	I could be retarding
you could be retarding
she could be retarding
we could be retarding
you could be retarding
they could be retarding	I could have retarded
you could have retarded
she could have retarded
we could have retarded
you could have retarded
they could have retarded	I could have been retarding
you could have been retarding
she could have been retarding
we could have been retarding
you could have been retarding
they could have been retarding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not retard
you could not retard
she could not retard
we could not retard
you could not retard
they could not retard 	I could not be retarding
you could not be retarding
she could not be retarding
we could not be retarding
you could not be retarding
they could not be retarding	I could not have retarded
you could not have retarded
she could not have retarded
we could not have retarded
you could not have retarded
they could not have retarded	I could not have been retarding
you could not have been retarding
she could not have been retarding
we could not have been retarding
you could not have been retarding
they could not have been retarding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I retard?
could you retard?
could she retard?
could we retard?
could you retard?
could they retard? 	could I be retarding?
could you be retarding?
could she be retarding?
could we be retarding?
could you be retarding?
could they be retarding? 	could I have retarded?
could you have retarded?
could she have retarded?
could we have retarded?
could you have retarded?
could they have retarded? 	could I have been retarding?
could you have been retarding?
could she have been retarding?
could we have been retarding?
could you have been retarding?
could they have been retarding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not retard?
could you not retard?
could she not retard?
could we not retard?
could you not retard?
could they not retard? 	could I not be retarding?
could you not be retarding?
could she not be retarding?
could we not be retarding?
could you not be retarding?
could they not be retarding? 	could I not have retarded?
could you not have retarded?
could she not have retarded?
could we not have retarded?
could you not have retarded?
could they not have retarded? 	could I not have been retarding?
could you not have been retarding?
could she not have been retarding?
could we not have been retarding?
could you not have been retarding?
could they not have been retarding?