could crumple
Regular verb: crumple - crumpled- crumpled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could crumple
you could crumple
he could crumple
we could crumple
you could crumple
they could crumple 	I could be crumpling
you could be crumpling
he could be crumpling
we could be crumpling
you could be crumpling
they could be crumpling	I could have crumpled
you could have crumpled
he could have crumpled
we could have crumpled
you could have crumpled
they could have crumpled	I could have been crumpling
you could have been crumpling
he could have been crumpling
we could have been crumpling
you could have been crumpling
they could have been crumpling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not crumple
you could not crumple
he could not crumple
we could not crumple
you could not crumple
they could not crumple 	I could not be crumpling
you could not be crumpling
he could not be crumpling
we could not be crumpling
you could not be crumpling
they could not be crumpling	I could not have crumpled
you could not have crumpled
he could not have crumpled
we could not have crumpled
you could not have crumpled
they could not have crumpled	I could not have been crumpling
you could not have been crumpling
he could not have been crumpling
we could not have been crumpling
you could not have been crumpling
they could not have been crumpling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I crumple?
could you crumple?
could he crumple?
could we crumple?
could you crumple?
could they crumple? 	could I be crumpling?
could you be crumpling?
could he be crumpling?
could we be crumpling?
could you be crumpling?
could they be crumpling? 	could I have crumpled?
could you have crumpled?
could he have crumpled?
could we have crumpled?
could you have crumpled?
could they have crumpled? 	could I have been crumpling?
could you have been crumpling?
could he have been crumpling?
could we have been crumpling?
could you have been crumpling?
could they have been crumpling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not crumple?
could you not crumple?
could he not crumple?
could we not crumple?
could you not crumple?
could they not crumple? 	could I not be crumpling?
could you not be crumpling?
could he not be crumpling?
could we not be crumpling?
could you not be crumpling?
could they not be crumpling? 	could I not have crumpled?
could you not have crumpled?
could he not have crumpled?
could we not have crumpled?
could you not have crumpled?
could they not have crumpled? 	could I not have been crumpling?
could you not have been crumpling?
could he not have been crumpling?
could we not have been crumpling?
could you not have been crumpling?
could they not have been crumpling?