could stale
Regular verb: stale - staled- staled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could stale
you could stale
she could stale
we could stale
you could stale
they could stale 	I could be staling
you could be staling
she could be staling
we could be staling
you could be staling
they could be staling	I could have staled
you could have staled
she could have staled
we could have staled
you could have staled
they could have staled	I could have been staling
you could have been staling
she could have been staling
we could have been staling
you could have been staling
they could have been staling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't stale
you couldn't stale
she couldn't stale
we couldn't stale
you couldn't stale
they couldn't stale 	I couldn't be staling
you couldn't be staling
she couldn't be staling
we couldn't be staling
you couldn't be staling
they couldn't be staling	I couldn't have staled
you couldn't have staled
she couldn't have staled
we couldn't have staled
you couldn't have staled
they couldn't have staled	I couldn't have been staling
you couldn't have been staling
she couldn't have been staling
we couldn't have been staling
you couldn't have been staling
they couldn't have been staling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I stale?
could you stale?
could she stale?
could we stale?
could you stale?
could they stale? 	could I be staling?
could you be staling?
could she be staling?
could we be staling?
could you be staling?
could they be staling? 	could I have staled?
could you have staled?
could she have staled?
could we have staled?
could you have staled?
could they have staled? 	could I have been staling?
could you have been staling?
could she have been staling?
could we have been staling?
could you have been staling?
could they have been staling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I stale?
couldn't you stale?
couldn't she stale?
couldn't we stale?
couldn't you stale?
couldn't they stale? 	couldn't I be staling?
couldn't you be staling?
couldn't she be staling?
couldn't we be staling?
couldn't you be staling?
couldn't they be staling? 	couldn't I have staled?
couldn't you have staled?
couldn't she have staled?
couldn't we have staled?
couldn't you have staled?
couldn't they have staled? 	couldn't I have been staling?
couldn't you have been staling?
couldn't she have been staling?
couldn't we have been staling?
couldn't you have been staling?
couldn't they have been staling?