can hammer
Regular verb: hammer - hammered- hammered

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

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

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

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