could harden
Regular verb: harden - hardened- hardened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could harden
you could harden
she could harden
we could harden
you could harden
they could harden 	I could be hardening
you could be hardening
she could be hardening
we could be hardening
you could be hardening
they could be hardening	I could have hardened
you could have hardened
she could have hardened
we could have hardened
you could have hardened
they could have hardened	I could have been hardening
you could have been hardening
she could have been hardening
we could have been hardening
you could have been hardening
they could have been hardening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't harden
you couldn't harden
she couldn't harden
we couldn't harden
you couldn't harden
they couldn't harden 	I couldn't be hardening
you couldn't be hardening
she couldn't be hardening
we couldn't be hardening
you couldn't be hardening
they couldn't be hardening	I couldn't have hardened
you couldn't have hardened
she couldn't have hardened
we couldn't have hardened
you couldn't have hardened
they couldn't have hardened	I couldn't have been hardening
you couldn't have been hardening
she couldn't have been hardening
we couldn't have been hardening
you couldn't have been hardening
they couldn't have been hardening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I harden?
could you harden?
could she harden?
could we harden?
could you harden?
could they harden? 	could I be hardening?
could you be hardening?
could she be hardening?
could we be hardening?
could you be hardening?
could they be hardening? 	could I have hardened?
could you have hardened?
could she have hardened?
could we have hardened?
could you have hardened?
could they have hardened? 	could I have been hardening?
could you have been hardening?
could she have been hardening?
could we have been hardening?
could you have been hardening?
could they have been hardening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I harden?
couldn't you harden?
couldn't she harden?
couldn't we harden?
couldn't you harden?
couldn't they harden? 	couldn't I be hardening?
couldn't you be hardening?
couldn't she be hardening?
couldn't we be hardening?
couldn't you be hardening?
couldn't they be hardening? 	couldn't I have hardened?
couldn't you have hardened?
couldn't she have hardened?
couldn't we have hardened?
couldn't you have hardened?
couldn't they have hardened? 	couldn't I have been hardening?
couldn't you have been hardening?
couldn't she have been hardening?
couldn't we have been hardening?
couldn't you have been hardening?
couldn't they have been hardening?