could perk
Regular verb: perk - perked- perked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could perk
you could perk
she could perk
we could perk
you could perk
they could perk 	I could be perking
you could be perking
she could be perking
we could be perking
you could be perking
they could be perking	I could have perked
you could have perked
she could have perked
we could have perked
you could have perked
they could have perked	I could have been perking
you could have been perking
she could have been perking
we could have been perking
you could have been perking
they could have been perking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not perk
you could not perk
she could not perk
we could not perk
you could not perk
they could not perk 	I could not be perking
you could not be perking
she could not be perking
we could not be perking
you could not be perking
they could not be perking	I could not have perked
you could not have perked
she could not have perked
we could not have perked
you could not have perked
they could not have perked	I could not have been perking
you could not have been perking
she could not have been perking
we could not have been perking
you could not have been perking
they could not have been perking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I perk?
could you perk?
could she perk?
could we perk?
could you perk?
could they perk? 	could I be perking?
could you be perking?
could she be perking?
could we be perking?
could you be perking?
could they be perking? 	could I have perked?
could you have perked?
could she have perked?
could we have perked?
could you have perked?
could they have perked? 	could I have been perking?
could you have been perking?
could she have been perking?
could we have been perking?
could you have been perking?
could they have been perking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not perk?
could you not perk?
could she not perk?
could we not perk?
could you not perk?
could they not perk? 	could I not be perking?
could you not be perking?
could she not be perking?
could we not be perking?
could you not be perking?
could they not be perking? 	could I not have perked?
could you not have perked?
could she not have perked?
could we not have perked?
could you not have perked?
could they not have perked? 	could I not have been perking?
could you not have been perking?
could she not have been perking?
could we not have been perking?
could you not have been perking?
could they not have been perking?