could yap yap
Regular verb: yap yap - yap yaped- yap yaped

, this verb may not exist. Conjugation is given as example.

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could yap yap
you could yap yap
he could yap yap
we could yap yap
you could yap yap
they could yap yap 	I could be yap yaping
you could be yap yaping
he could be yap yaping
we could be yap yaping
you could be yap yaping
they could be yap yaping	I could have yap yaped
you could have yap yaped
he could have yap yaped
we could have yap yaped
you could have yap yaped
they could have yap yaped	I could have been yap yaping
you could have been yap yaping
he could have been yap yaping
we could have been yap yaping
you could have been yap yaping
they could have been yap yaping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't yap yap
you couldn't yap yap
he couldn't yap yap
we couldn't yap yap
you couldn't yap yap
they couldn't yap yap 	I couldn't be yap yaping
you couldn't be yap yaping
he couldn't be yap yaping
we couldn't be yap yaping
you couldn't be yap yaping
they couldn't be yap yaping	I couldn't have yap yaped
you couldn't have yap yaped
he couldn't have yap yaped
we couldn't have yap yaped
you couldn't have yap yaped
they couldn't have yap yaped	I couldn't have been yap yaping
you couldn't have been yap yaping
he couldn't have been yap yaping
we couldn't have been yap yaping
you couldn't have been yap yaping
they couldn't have been yap yaping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I yap yap?
could you yap yap?
could he yap yap?
could we yap yap?
could you yap yap?
could they yap yap? 	could I be yap yaping?
could you be yap yaping?
could he be yap yaping?
could we be yap yaping?
could you be yap yaping?
could they be yap yaping? 	could I have yap yaped?
could you have yap yaped?
could he have yap yaped?
could we have yap yaped?
could you have yap yaped?
could they have yap yaped? 	could I have been yap yaping?
could you have been yap yaping?
could he have been yap yaping?
could we have been yap yaping?
could you have been yap yaping?
could they have been yap yaping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I yap yap?
couldn't you yap yap?
couldn't he yap yap?
couldn't we yap yap?
couldn't you yap yap?
couldn't they yap yap? 	couldn't I be yap yaping?
couldn't you be yap yaping?
couldn't he be yap yaping?
couldn't we be yap yaping?
couldn't you be yap yaping?
couldn't they be yap yaping? 	couldn't I have yap yaped?
couldn't you have yap yaped?
couldn't he have yap yaped?
couldn't we have yap yaped?
couldn't you have yap yaped?
couldn't they have yap yaped? 	couldn't I have been yap yaping?
couldn't you have been yap yaping?
couldn't he have been yap yaping?
couldn't we have been yap yaping?
couldn't you have been yap yaping?
couldn't they have been yap yaping?