could cube
Regular verb: cube - cubed- cubed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could cube
you could cube
he could cube
we could cube
you could cube
they could cube 	I could be cubing
you could be cubing
he could be cubing
we could be cubing
you could be cubing
they could be cubing	I could have cubed
you could have cubed
he could have cubed
we could have cubed
you could have cubed
they could have cubed	I could have been cubing
you could have been cubing
he could have been cubing
we could have been cubing
you could have been cubing
they could have been cubing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not cube
you could not cube
he could not cube
we could not cube
you could not cube
they could not cube 	I could not be cubing
you could not be cubing
he could not be cubing
we could not be cubing
you could not be cubing
they could not be cubing	I could not have cubed
you could not have cubed
he could not have cubed
we could not have cubed
you could not have cubed
they could not have cubed	I could not have been cubing
you could not have been cubing
he could not have been cubing
we could not have been cubing
you could not have been cubing
they could not have been cubing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I cube?
could you cube?
could he cube?
could we cube?
could you cube?
could they cube? 	could I be cubing?
could you be cubing?
could he be cubing?
could we be cubing?
could you be cubing?
could they be cubing? 	could I have cubed?
could you have cubed?
could he have cubed?
could we have cubed?
could you have cubed?
could they have cubed? 	could I have been cubing?
could you have been cubing?
could he have been cubing?
could we have been cubing?
could you have been cubing?
could they have been cubing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not cube?
could you not cube?
could he not cube?
could we not cube?
could you not cube?
could they not cube? 	could I not be cubing?
could you not be cubing?
could he not be cubing?
could we not be cubing?
could you not be cubing?
could they not be cubing? 	could I not have cubed?
could you not have cubed?
could he not have cubed?
could we not have cubed?
could you not have cubed?
could they not have cubed? 	could I not have been cubing?
could you not have been cubing?
could he not have been cubing?
could we not have been cubing?
could you not have been cubing?
could they not have been cubing?