can lumber
Regular verb: lumber - lumbered- lumbered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can lumber
you can lumber
she can lumber
we can lumber
you can lumber
they can lumber 	I can be lumbering
you can be lumbering
she can be lumbering
we can be lumbering
you can be lumbering
they can be lumbering	I can have lumbered
you can have lumbered
she can have lumbered
we can have lumbered
you can have lumbered
they can have lumbered	I can have been lumbering
you can have been lumbering
she can have been lumbering
we can have been lumbering
you can have been lumbering
they can have been lumbering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot lumber
you cannot lumber
she cannot lumber
we cannot lumber
you cannot lumber
they cannot lumber 	I cannot be lumbering
you cannot be lumbering
she cannot be lumbering
we cannot be lumbering
you cannot be lumbering
they cannot be lumbering	I cannot have lumbered
you cannot have lumbered
she cannot have lumbered
we cannot have lumbered
you cannot have lumbered
they cannot have lumbered	I cannot have been lumbering
you cannot have been lumbering
she cannot have been lumbering
we cannot have been lumbering
you cannot have been lumbering
they cannot have been lumbering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I lumber?
can you lumber?
can she lumber?
can we lumber?
can you lumber?
can they lumber? 	can I be lumbering?
can you be lumbering?
can she be lumbering?
can we be lumbering?
can you be lumbering?
can they be lumbering? 	can I have lumbered?
can you have lumbered?
can she have lumbered?
can we have lumbered?
can you have lumbered?
can they have lumbered? 	can I have been lumbering?
can you have been lumbering?
can she have been lumbering?
can we have been lumbering?
can you have been lumbering?
can they have been lumbering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not lumber?
can you not lumber?
can she not lumber?
can we not lumber?
can you not lumber?
can they not lumber? 	can I not be lumbering?
can you not be lumbering?
can she not be lumbering?
can we not be lumbering?
can you not be lumbering?
can they not be lumbering? 	can I not have lumbered?
can you not have lumbered?
can she not have lumbered?
can we not have lumbered?
can you not have lumbered?
can they not have lumbered? 	can I not have been lumbering?
can you not have been lumbering?
can she not have been lumbering?
can we not have been lumbering?
can you not have been lumbering?
can they not have been lumbering?