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 couldn't crumple
you couldn't crumple
he couldn't crumple
we couldn't crumple
you couldn't crumple
they couldn't crumple 	I couldn't be crumpling
you couldn't be crumpling
he couldn't be crumpling
we couldn't be crumpling
you couldn't be crumpling
they couldn't be crumpling	I couldn't have crumpled
you couldn't have crumpled
he couldn't have crumpled
we couldn't have crumpled
you couldn't have crumpled
they couldn't have crumpled	I couldn't have been crumpling
you couldn't have been crumpling
he couldn't have been crumpling
we couldn't have been crumpling
you couldn't have been crumpling
they couldn't 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 	
couldn't I crumple?
couldn't you crumple?
couldn't he crumple?
couldn't we crumple?
couldn't you crumple?
couldn't they crumple? 	couldn't I be crumpling?
couldn't you be crumpling?
couldn't he be crumpling?
couldn't we be crumpling?
couldn't you be crumpling?
couldn't they be crumpling? 	couldn't I have crumpled?
couldn't you have crumpled?
couldn't he have crumpled?
couldn't we have crumpled?
couldn't you have crumpled?
couldn't they have crumpled? 	couldn't I have been crumpling?
couldn't you have been crumpling?
couldn't he have been crumpling?
couldn't we have been crumpling?
couldn't you have been crumpling?
couldn't they have been crumpling?