could grate
Regular verb: grate - grated- grated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could grate
you could grate
he could grate
we could grate
you could grate
they could grate 	I could be grating
you could be grating
he could be grating
we could be grating
you could be grating
they could be grating	I could have grated
you could have grated
he could have grated
we could have grated
you could have grated
they could have grated	I could have been grating
you could have been grating
he could have been grating
we could have been grating
you could have been grating
they could have been grating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't grate
you couldn't grate
he couldn't grate
we couldn't grate
you couldn't grate
they couldn't grate 	I couldn't be grating
you couldn't be grating
he couldn't be grating
we couldn't be grating
you couldn't be grating
they couldn't be grating	I couldn't have grated
you couldn't have grated
he couldn't have grated
we couldn't have grated
you couldn't have grated
they couldn't have grated	I couldn't have been grating
you couldn't have been grating
he couldn't have been grating
we couldn't have been grating
you couldn't have been grating
they couldn't have been grating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I grate?
could you grate?
could he grate?
could we grate?
could you grate?
could they grate? 	could I be grating?
could you be grating?
could he be grating?
could we be grating?
could you be grating?
could they be grating? 	could I have grated?
could you have grated?
could he have grated?
could we have grated?
could you have grated?
could they have grated? 	could I have been grating?
could you have been grating?
could he have been grating?
could we have been grating?
could you have been grating?
could they have been grating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I grate?
couldn't you grate?
couldn't he grate?
couldn't we grate?
couldn't you grate?
couldn't they grate? 	couldn't I be grating?
couldn't you be grating?
couldn't he be grating?
couldn't we be grating?
couldn't you be grating?
couldn't they be grating? 	couldn't I have grated?
couldn't you have grated?
couldn't he have grated?
couldn't we have grated?
couldn't you have grated?
couldn't they have grated? 	couldn't I have been grating?
couldn't you have been grating?
couldn't he have been grating?
couldn't we have been grating?
couldn't you have been grating?
couldn't they have been grating?