could drub
Regular verb: drub - drubbed- drubbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could drub
you could drub
she could drub
we could drub
you could drub
they could drub 	I could be drubbing
you could be drubbing
she could be drubbing
we could be drubbing
you could be drubbing
they could be drubbing	I could have drubbed
you could have drubbed
she could have drubbed
we could have drubbed
you could have drubbed
they could have drubbed	I could have been drubbing
you could have been drubbing
she could have been drubbing
we could have been drubbing
you could have been drubbing
they could have been drubbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not drub
you could not drub
she could not drub
we could not drub
you could not drub
they could not drub 	I could not be drubbing
you could not be drubbing
she could not be drubbing
we could not be drubbing
you could not be drubbing
they could not be drubbing	I could not have drubbed
you could not have drubbed
she could not have drubbed
we could not have drubbed
you could not have drubbed
they could not have drubbed	I could not have been drubbing
you could not have been drubbing
she could not have been drubbing
we could not have been drubbing
you could not have been drubbing
they could not have been drubbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I drub?
could you drub?
could she drub?
could we drub?
could you drub?
could they drub? 	could I be drubbing?
could you be drubbing?
could she be drubbing?
could we be drubbing?
could you be drubbing?
could they be drubbing? 	could I have drubbed?
could you have drubbed?
could she have drubbed?
could we have drubbed?
could you have drubbed?
could they have drubbed? 	could I have been drubbing?
could you have been drubbing?
could she have been drubbing?
could we have been drubbing?
could you have been drubbing?
could they have been drubbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not drub?
could you not drub?
could she not drub?
could we not drub?
could you not drub?
could they not drub? 	could I not be drubbing?
could you not be drubbing?
could she not be drubbing?
could we not be drubbing?
could you not be drubbing?
could they not be drubbing? 	could I not have drubbed?
could you not have drubbed?
could she not have drubbed?
could we not have drubbed?
could you not have drubbed?
could they not have drubbed? 	could I not have been drubbing?
could you not have been drubbing?
could she not have been drubbing?
could we not have been drubbing?
could you not have been drubbing?
could they not have been drubbing?