could pi
Regular verb: pi - pied- pied

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could pi
you could pi
she could pi
we could pi
you could pi
they could pi 	I could be piing
you could be piing
she could be piing
we could be piing
you could be piing
they could be piing	I could have pied
you could have pied
she could have pied
we could have pied
you could have pied
they could have pied	I could have been piing
you could have been piing
she could have been piing
we could have been piing
you could have been piing
they could have been piing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't pi
you couldn't pi
she couldn't pi
we couldn't pi
you couldn't pi
they couldn't pi 	I couldn't be piing
you couldn't be piing
she couldn't be piing
we couldn't be piing
you couldn't be piing
they couldn't be piing	I couldn't have pied
you couldn't have pied
she couldn't have pied
we couldn't have pied
you couldn't have pied
they couldn't have pied	I couldn't have been piing
you couldn't have been piing
she couldn't have been piing
we couldn't have been piing
you couldn't have been piing
they couldn't have been piing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I pi?
could you pi?
could she pi?
could we pi?
could you pi?
could they pi? 	could I be piing?
could you be piing?
could she be piing?
could we be piing?
could you be piing?
could they be piing? 	could I have pied?
could you have pied?
could she have pied?
could we have pied?
could you have pied?
could they have pied? 	could I have been piing?
could you have been piing?
could she have been piing?
could we have been piing?
could you have been piing?
could they have been piing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I pi?
couldn't you pi?
couldn't she pi?
couldn't we pi?
couldn't you pi?
couldn't they pi? 	couldn't I be piing?
couldn't you be piing?
couldn't she be piing?
couldn't we be piing?
couldn't you be piing?
couldn't they be piing? 	couldn't I have pied?
couldn't you have pied?
couldn't she have pied?
couldn't we have pied?
couldn't you have pied?
couldn't they have pied? 	couldn't I have been piing?
couldn't you have been piing?
couldn't she have been piing?
couldn't we have been piing?
couldn't you have been piing?
couldn't they have been piing?