could crinkle
Regular verb: crinkle - crinkled- crinkled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could crinkle
you could crinkle
she could crinkle
we could crinkle
you could crinkle
they could crinkle 	I could be crinkling
you could be crinkling
she could be crinkling
we could be crinkling
you could be crinkling
they could be crinkling	I could have crinkled
you could have crinkled
she could have crinkled
we could have crinkled
you could have crinkled
they could have crinkled	I could have been crinkling
you could have been crinkling
she could have been crinkling
we could have been crinkling
you could have been crinkling
they could have been crinkling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't crinkle
you couldn't crinkle
she couldn't crinkle
we couldn't crinkle
you couldn't crinkle
they couldn't crinkle 	I couldn't be crinkling
you couldn't be crinkling
she couldn't be crinkling
we couldn't be crinkling
you couldn't be crinkling
they couldn't be crinkling	I couldn't have crinkled
you couldn't have crinkled
she couldn't have crinkled
we couldn't have crinkled
you couldn't have crinkled
they couldn't have crinkled	I couldn't have been crinkling
you couldn't have been crinkling
she couldn't have been crinkling
we couldn't have been crinkling
you couldn't have been crinkling
they couldn't have been crinkling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I crinkle?
could you crinkle?
could she crinkle?
could we crinkle?
could you crinkle?
could they crinkle? 	could I be crinkling?
could you be crinkling?
could she be crinkling?
could we be crinkling?
could you be crinkling?
could they be crinkling? 	could I have crinkled?
could you have crinkled?
could she have crinkled?
could we have crinkled?
could you have crinkled?
could they have crinkled? 	could I have been crinkling?
could you have been crinkling?
could she have been crinkling?
could we have been crinkling?
could you have been crinkling?
could they have been crinkling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I crinkle?
couldn't you crinkle?
couldn't she crinkle?
couldn't we crinkle?
couldn't you crinkle?
couldn't they crinkle? 	couldn't I be crinkling?
couldn't you be crinkling?
couldn't she be crinkling?
couldn't we be crinkling?
couldn't you be crinkling?
couldn't they be crinkling? 	couldn't I have crinkled?
couldn't you have crinkled?
couldn't she have crinkled?
couldn't we have crinkled?
couldn't you have crinkled?
couldn't they have crinkled? 	couldn't I have been crinkling?
couldn't you have been crinkling?
couldn't she have been crinkling?
couldn't we have been crinkling?
couldn't you have been crinkling?
couldn't they have been crinkling?