can hammer
Regular verb: hammer - hammered- hammered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can hammer
you can hammer
she can hammer
we can hammer
you can hammer
they can hammer 	I can be hammering
you can be hammering
she can be hammering
we can be hammering
you can be hammering
they can be hammering	I can have hammered
you can have hammered
she 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
she 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 cannot hammer
you cannot hammer
she cannot hammer
we cannot hammer
you cannot hammer
they cannot hammer 	I cannot be hammering
you cannot be hammering
she cannot be hammering
we cannot be hammering
you cannot be hammering
they cannot be hammering	I cannot have hammered
you cannot have hammered
she cannot have hammered
we cannot have hammered
you cannot have hammered
they cannot have hammered	I cannot have been hammering
you cannot have been hammering
she cannot have been hammering
we cannot have been hammering
you cannot have been hammering
they cannot have been hammering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I hammer?
can you hammer?
can she hammer?
can we hammer?
can you hammer?
can they hammer? 	can I be hammering?
can you be hammering?
can she be hammering?
can we be hammering?
can you be hammering?
can they be hammering? 	can I have hammered?
can you have hammered?
can she 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 she 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 I not hammer?
can you not hammer?
can she not hammer?
can we not hammer?
can you not hammer?
can they not hammer? 	can I not be hammering?
can you not be hammering?
can she not be hammering?
can we not be hammering?
can you not be hammering?
can they not be hammering? 	can I not have hammered?
can you not have hammered?
can she not have hammered?
can we not have hammered?
can you not have hammered?
can they not have hammered? 	can I not have been hammering?
can you not have been hammering?
can she not have been hammering?
can we not have been hammering?
can you not have been hammering?
can they not have been hammering?