could hammer
Regular verb: hammer - hammered- hammered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could hammer
you could hammer
he could hammer
we could hammer
you could hammer
they could hammer 	I could be hammering
you could be hammering
he could be hammering
we could be hammering
you could be hammering
they could be hammering	I could have hammered
you could have hammered
he could have hammered
we could have hammered
you could have hammered
they could have hammered	I could have been hammering
you could have been hammering
he could have been hammering
we could have been hammering
you could have been hammering
they could have been hammering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't hammer
you couldn't hammer
he couldn't hammer
we couldn't hammer
you couldn't hammer
they couldn't hammer 	I couldn't be hammering
you couldn't be hammering
he couldn't be hammering
we couldn't be hammering
you couldn't be hammering
they couldn't be hammering	I couldn't have hammered
you couldn't have hammered
he couldn't have hammered
we couldn't have hammered
you couldn't have hammered
they couldn't have hammered	I couldn't have been hammering
you couldn't have been hammering
he couldn't have been hammering
we couldn't have been hammering
you couldn't have been hammering
they couldn't have been hammering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I hammer?
could you hammer?
could he hammer?
could we hammer?
could you hammer?
could they hammer? 	could I be hammering?
could you be hammering?
could he be hammering?
could we be hammering?
could you be hammering?
could they be hammering? 	could I have hammered?
could you have hammered?
could he have hammered?
could we have hammered?
could you have hammered?
could they have hammered? 	could I have been hammering?
could you have been hammering?
could he have been hammering?
could we have been hammering?
could you have been hammering?
could they have been hammering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I hammer?
couldn't you hammer?
couldn't he hammer?
couldn't we hammer?
couldn't you hammer?
couldn't they hammer? 	couldn't I be hammering?
couldn't you be hammering?
couldn't he be hammering?
couldn't we be hammering?
couldn't you be hammering?
couldn't they be hammering? 	couldn't I have hammered?
couldn't you have hammered?
couldn't he have hammered?
couldn't we have hammered?
couldn't you have hammered?
couldn't they have hammered? 	couldn't I have been hammering?
couldn't you have been hammering?
couldn't he have been hammering?
couldn't we have been hammering?
couldn't you have been hammering?
couldn't they have been hammering?