can harden
Regular verb: harden - hardened- hardened

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

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot harden
you cannot harden
he cannot harden
we cannot harden
you cannot harden
they cannot harden 	I cannot be hardening
you cannot be hardening
he cannot be hardening
we cannot be hardening
you cannot be hardening
they cannot be hardening	I cannot have hardened
you cannot have hardened
he cannot have hardened
we cannot have hardened
you cannot have hardened
they cannot have hardened	I cannot have been hardening
you cannot have been hardening
he cannot have been hardening
we cannot have been hardening
you cannot have been hardening
they cannot have been hardening	

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

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not harden?
can you not harden?
can he not harden?
can we not harden?
can you not harden?
can they not harden? 	can I not be hardening?
can you not be hardening?
can he not be hardening?
can we not be hardening?
can you not be hardening?
can they not be hardening? 	can I not have hardened?
can you not have hardened?
can he not have hardened?
can we not have hardened?
can you not have hardened?
can they not have hardened? 	can I not have been hardening?
can you not have been hardening?
can he not have been hardening?
can we not have been hardening?
can you not have been hardening?
can they not have been hardening?