could ground
Regular verb: ground - grounded- grounded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could ground
you could ground
she could ground
we could ground
you could ground
they could ground 	I could be grounding
you could be grounding
she could be grounding
we could be grounding
you could be grounding
they could be grounding	I could have grounded
you could have grounded
she could have grounded
we could have grounded
you could have grounded
they could have grounded	I could have been grounding
you could have been grounding
she could have been grounding
we could have been grounding
you could have been grounding
they could have been grounding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not ground
you could not ground
she could not ground
we could not ground
you could not ground
they could not ground 	I could not be grounding
you could not be grounding
she could not be grounding
we could not be grounding
you could not be grounding
they could not be grounding	I could not have grounded
you could not have grounded
she could not have grounded
we could not have grounded
you could not have grounded
they could not have grounded	I could not have been grounding
you could not have been grounding
she could not have been grounding
we could not have been grounding
you could not have been grounding
they could not have been grounding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I ground?
could you ground?
could she ground?
could we ground?
could you ground?
could they ground? 	could I be grounding?
could you be grounding?
could she be grounding?
could we be grounding?
could you be grounding?
could they be grounding? 	could I have grounded?
could you have grounded?
could she have grounded?
could we have grounded?
could you have grounded?
could they have grounded? 	could I have been grounding?
could you have been grounding?
could she have been grounding?
could we have been grounding?
could you have been grounding?
could they have been grounding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not ground?
could you not ground?
could she not ground?
could we not ground?
could you not ground?
could they not ground? 	could I not be grounding?
could you not be grounding?
could she not be grounding?
could we not be grounding?
could you not be grounding?
could they not be grounding? 	could I not have grounded?
could you not have grounded?
could she not have grounded?
could we not have grounded?
could you not have grounded?
could they not have grounded? 	could I not have been grounding?
could you not have been grounding?
could she not have been grounding?
could we not have been grounding?
could you not have been grounding?
could they not have been grounding?