could overharden
Regular verb: overharden - overhardened- overhardened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could overharden
you could overharden
he could overharden
we could overharden
you could overharden
they could overharden 	I could be overhardening
you could be overhardening
he could be overhardening
we could be overhardening
you could be overhardening
they could be overhardening	I could have overhardened
you could have overhardened
he could have overhardened
we could have overhardened
you could have overhardened
they could have overhardened	I could have been overhardening
you could have been overhardening
he could have been overhardening
we could have been overhardening
you could have been overhardening
they could have been overhardening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not overharden
you could not overharden
he could not overharden
we could not overharden
you could not overharden
they could not overharden 	I could not be overhardening
you could not be overhardening
he could not be overhardening
we could not be overhardening
you could not be overhardening
they could not be overhardening	I could not have overhardened
you could not have overhardened
he could not have overhardened
we could not have overhardened
you could not have overhardened
they could not have overhardened	I could not have been overhardening
you could not have been overhardening
he could not have been overhardening
we could not have been overhardening
you could not have been overhardening
they could not have been overhardening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I overharden?
could you overharden?
could he overharden?
could we overharden?
could you overharden?
could they overharden? 	could I be overhardening?
could you be overhardening?
could he be overhardening?
could we be overhardening?
could you be overhardening?
could they be overhardening? 	could I have overhardened?
could you have overhardened?
could he have overhardened?
could we have overhardened?
could you have overhardened?
could they have overhardened? 	could I have been overhardening?
could you have been overhardening?
could he have been overhardening?
could we have been overhardening?
could you have been overhardening?
could they have been overhardening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not overharden?
could you not overharden?
could he not overharden?
could we not overharden?
could you not overharden?
could they not overharden? 	could I not be overhardening?
could you not be overhardening?
could he not be overhardening?
could we not be overhardening?
could you not be overhardening?
could they not be overhardening? 	could I not have overhardened?
could you not have overhardened?
could he not have overhardened?
could we not have overhardened?
could you not have overhardened?
could they not have overhardened? 	could I not have been overhardening?
could you not have been overhardening?
could he not have been overhardening?
could we not have been overhardening?
could you not have been overhardening?
could they not have been overhardening?