could piggyback
Regular verb: piggyback - piggybacked- piggybacked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could piggyback
you could piggyback
he could piggyback
we could piggyback
you could piggyback
they could piggyback 	I could be piggybacking
you could be piggybacking
he could be piggybacking
we could be piggybacking
you could be piggybacking
they could be piggybacking	I could have piggybacked
you could have piggybacked
he could have piggybacked
we could have piggybacked
you could have piggybacked
they could have piggybacked	I could have been piggybacking
you could have been piggybacking
he could have been piggybacking
we could have been piggybacking
you could have been piggybacking
they could have been piggybacking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't piggyback
you couldn't piggyback
he couldn't piggyback
we couldn't piggyback
you couldn't piggyback
they couldn't piggyback 	I couldn't be piggybacking
you couldn't be piggybacking
he couldn't be piggybacking
we couldn't be piggybacking
you couldn't be piggybacking
they couldn't be piggybacking	I couldn't have piggybacked
you couldn't have piggybacked
he couldn't have piggybacked
we couldn't have piggybacked
you couldn't have piggybacked
they couldn't have piggybacked	I couldn't have been piggybacking
you couldn't have been piggybacking
he couldn't have been piggybacking
we couldn't have been piggybacking
you couldn't have been piggybacking
they couldn't have been piggybacking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I piggyback?
could you piggyback?
could he piggyback?
could we piggyback?
could you piggyback?
could they piggyback? 	could I be piggybacking?
could you be piggybacking?
could he be piggybacking?
could we be piggybacking?
could you be piggybacking?
could they be piggybacking? 	could I have piggybacked?
could you have piggybacked?
could he have piggybacked?
could we have piggybacked?
could you have piggybacked?
could they have piggybacked? 	could I have been piggybacking?
could you have been piggybacking?
could he have been piggybacking?
could we have been piggybacking?
could you have been piggybacking?
could they have been piggybacking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I piggyback?
couldn't you piggyback?
couldn't he piggyback?
couldn't we piggyback?
couldn't you piggyback?
couldn't they piggyback? 	couldn't I be piggybacking?
couldn't you be piggybacking?
couldn't he be piggybacking?
couldn't we be piggybacking?
couldn't you be piggybacking?
couldn't they be piggybacking? 	couldn't I have piggybacked?
couldn't you have piggybacked?
couldn't he have piggybacked?
couldn't we have piggybacked?
couldn't you have piggybacked?
couldn't they have piggybacked? 	couldn't I have been piggybacking?
couldn't you have been piggybacking?
couldn't he have been piggybacking?
couldn't we have been piggybacking?
couldn't you have been piggybacking?
couldn't they have been piggybacking?