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