could yawp
Regular verb: yawp - yawped- yawped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could yawp
you could yawp
he could yawp
we could yawp
you could yawp
they could yawp 	I could be yawping
you could be yawping
he could be yawping
we could be yawping
you could be yawping
they could be yawping	I could have yawped
you could have yawped
he could have yawped
we could have yawped
you could have yawped
they could have yawped	I could have been yawping
you could have been yawping
he could have been yawping
we could have been yawping
you could have been yawping
they could have been yawping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't yawp
you couldn't yawp
he couldn't yawp
we couldn't yawp
you couldn't yawp
they couldn't yawp 	I couldn't be yawping
you couldn't be yawping
he couldn't be yawping
we couldn't be yawping
you couldn't be yawping
they couldn't be yawping	I couldn't have yawped
you couldn't have yawped
he couldn't have yawped
we couldn't have yawped
you couldn't have yawped
they couldn't have yawped	I couldn't have been yawping
you couldn't have been yawping
he couldn't have been yawping
we couldn't have been yawping
you couldn't have been yawping
they couldn't have been yawping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I yawp?
could you yawp?
could he yawp?
could we yawp?
could you yawp?
could they yawp? 	could I be yawping?
could you be yawping?
could he be yawping?
could we be yawping?
could you be yawping?
could they be yawping? 	could I have yawped?
could you have yawped?
could he have yawped?
could we have yawped?
could you have yawped?
could they have yawped? 	could I have been yawping?
could you have been yawping?
could he have been yawping?
could we have been yawping?
could you have been yawping?
could they have been yawping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I yawp?
couldn't you yawp?
couldn't he yawp?
couldn't we yawp?
couldn't you yawp?
couldn't they yawp? 	couldn't I be yawping?
couldn't you be yawping?
couldn't he be yawping?
couldn't we be yawping?
couldn't you be yawping?
couldn't they be yawping? 	couldn't I have yawped?
couldn't you have yawped?
couldn't he have yawped?
couldn't we have yawped?
couldn't you have yawped?
couldn't they have yawped? 	couldn't I have been yawping?
couldn't you have been yawping?
couldn't he have been yawping?
couldn't we have been yawping?
couldn't you have been yawping?
couldn't they have been yawping?