could intergrade
Regular verb: intergrade - intergraded- intergraded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could intergrade
you could intergrade
he could intergrade
we could intergrade
you could intergrade
they could intergrade 	I could be intergrading
you could be intergrading
he could be intergrading
we could be intergrading
you could be intergrading
they could be intergrading	I could have intergraded
you could have intergraded
he could have intergraded
we could have intergraded
you could have intergraded
they could have intergraded	I could have been intergrading
you could have been intergrading
he could have been intergrading
we could have been intergrading
you could have been intergrading
they could have been intergrading	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't intergrade
you couldn't intergrade
he couldn't intergrade
we couldn't intergrade
you couldn't intergrade
they couldn't intergrade 	I couldn't be intergrading
you couldn't be intergrading
he couldn't be intergrading
we couldn't be intergrading
you couldn't be intergrading
they couldn't be intergrading	I couldn't have intergraded
you couldn't have intergraded
he couldn't have intergraded
we couldn't have intergraded
you couldn't have intergraded
they couldn't have intergraded	I couldn't have been intergrading
you couldn't have been intergrading
he couldn't have been intergrading
we couldn't have been intergrading
you couldn't have been intergrading
they couldn't have been intergrading	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I intergrade?
could you intergrade?
could he intergrade?
could we intergrade?
could you intergrade?
could they intergrade? 	could I be intergrading?
could you be intergrading?
could he be intergrading?
could we be intergrading?
could you be intergrading?
could they be intergrading? 	could I have intergraded?
could you have intergraded?
could he have intergraded?
could we have intergraded?
could you have intergraded?
could they have intergraded? 	could I have been intergrading?
could you have been intergrading?
could he have been intergrading?
could we have been intergrading?
could you have been intergrading?
could they have been intergrading? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I intergrade?
couldn't you intergrade?
couldn't he intergrade?
couldn't we intergrade?
couldn't you intergrade?
couldn't they intergrade? 	couldn't I be intergrading?
couldn't you be intergrading?
couldn't he be intergrading?
couldn't we be intergrading?
couldn't you be intergrading?
couldn't they be intergrading? 	couldn't I have intergraded?
couldn't you have intergraded?
couldn't he have intergraded?
couldn't we have intergraded?
couldn't you have intergraded?
couldn't they have intergraded? 	couldn't I have been intergrading?
couldn't you have been intergrading?
couldn't he have been intergrading?
couldn't we have been intergrading?
couldn't you have been intergrading?
couldn't they have been intergrading?