could fib
Regular verb: fib - fibbed- fibbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could fib
you could fib
she could fib
we could fib
you could fib
they could fib 	I could be fibbing
you could be fibbing
she could be fibbing
we could be fibbing
you could be fibbing
they could be fibbing	I could have fibbed
you could have fibbed
she could have fibbed
we could have fibbed
you could have fibbed
they could have fibbed	I could have been fibbing
you could have been fibbing
she could have been fibbing
we could have been fibbing
you could have been fibbing
they could have been fibbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't fib
you couldn't fib
she couldn't fib
we couldn't fib
you couldn't fib
they couldn't fib 	I couldn't be fibbing
you couldn't be fibbing
she couldn't be fibbing
we couldn't be fibbing
you couldn't be fibbing
they couldn't be fibbing	I couldn't have fibbed
you couldn't have fibbed
she couldn't have fibbed
we couldn't have fibbed
you couldn't have fibbed
they couldn't have fibbed	I couldn't have been fibbing
you couldn't have been fibbing
she couldn't have been fibbing
we couldn't have been fibbing
you couldn't have been fibbing
they couldn't have been fibbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I fib?
could you fib?
could she fib?
could we fib?
could you fib?
could they fib? 	could I be fibbing?
could you be fibbing?
could she be fibbing?
could we be fibbing?
could you be fibbing?
could they be fibbing? 	could I have fibbed?
could you have fibbed?
could she have fibbed?
could we have fibbed?
could you have fibbed?
could they have fibbed? 	could I have been fibbing?
could you have been fibbing?
could she have been fibbing?
could we have been fibbing?
could you have been fibbing?
could they have been fibbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I fib?
couldn't you fib?
couldn't she fib?
couldn't we fib?
couldn't you fib?
couldn't they fib? 	couldn't I be fibbing?
couldn't you be fibbing?
couldn't she be fibbing?
couldn't we be fibbing?
couldn't you be fibbing?
couldn't they be fibbing? 	couldn't I have fibbed?
couldn't you have fibbed?
couldn't she have fibbed?
couldn't we have fibbed?
couldn't you have fibbed?
couldn't they have fibbed? 	couldn't I have been fibbing?
couldn't you have been fibbing?
couldn't she have been fibbing?
couldn't we have been fibbing?
couldn't you have been fibbing?
couldn't they have been fibbing?