could vail
Regular verb: vail - vailed- vailed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could vail
you could vail
she could vail
we could vail
you could vail
they could vail 	I could be vailing
you could be vailing
she could be vailing
we could be vailing
you could be vailing
they could be vailing	I could have vailed
you could have vailed
she could have vailed
we could have vailed
you could have vailed
they could have vailed	I could have been vailing
you could have been vailing
she could have been vailing
we could have been vailing
you could have been vailing
they could have been vailing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't vail
you couldn't vail
she couldn't vail
we couldn't vail
you couldn't vail
they couldn't vail 	I couldn't be vailing
you couldn't be vailing
she couldn't be vailing
we couldn't be vailing
you couldn't be vailing
they couldn't be vailing	I couldn't have vailed
you couldn't have vailed
she couldn't have vailed
we couldn't have vailed
you couldn't have vailed
they couldn't have vailed	I couldn't have been vailing
you couldn't have been vailing
she couldn't have been vailing
we couldn't have been vailing
you couldn't have been vailing
they couldn't have been vailing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I vail?
could you vail?
could she vail?
could we vail?
could you vail?
could they vail? 	could I be vailing?
could you be vailing?
could she be vailing?
could we be vailing?
could you be vailing?
could they be vailing? 	could I have vailed?
could you have vailed?
could she have vailed?
could we have vailed?
could you have vailed?
could they have vailed? 	could I have been vailing?
could you have been vailing?
could she have been vailing?
could we have been vailing?
could you have been vailing?
could they have been vailing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I vail?
couldn't you vail?
couldn't she vail?
couldn't we vail?
couldn't you vail?
couldn't they vail? 	couldn't I be vailing?
couldn't you be vailing?
couldn't she be vailing?
couldn't we be vailing?
couldn't you be vailing?
couldn't they be vailing? 	couldn't I have vailed?
couldn't you have vailed?
couldn't she have vailed?
couldn't we have vailed?
couldn't you have vailed?
couldn't they have vailed? 	couldn't I have been vailing?
couldn't you have been vailing?
couldn't she have been vailing?
couldn't we have been vailing?
couldn't you have been vailing?
couldn't they have been vailing?