I could reharden you could reharden he could reharden we could reharden you could reharden they could reharden
V-ing form
I could be rehardening you could be rehardening he could be rehardening we could be rehardening you could be rehardening they could be rehardening
Perfect
I could have rehardened you could have rehardened he could have rehardened we could have rehardened you could have rehardened they could have rehardened
V-ing perfect
I could have been rehardening you could have been rehardening he could have been rehardening we could have been rehardening you could have been rehardening they could have been rehardening
Negation
Simple form
I couldn't reharden you couldn't reharden he couldn't reharden we couldn't reharden you couldn't reharden they couldn't reharden
V-ing form
I couldn't be rehardening you couldn't be rehardening he couldn't be rehardening we couldn't be rehardening you couldn't be rehardening they couldn't be rehardening
Perfect
I couldn't have rehardened you couldn't have rehardened he couldn't have rehardened we couldn't have rehardened you couldn't have rehardened they couldn't have rehardened
V-ing perfect
I couldn't have been rehardening you couldn't have been rehardening he couldn't have been rehardening we couldn't have been rehardening you couldn't have been rehardening they couldn't have been rehardening
Interrogative form
Simple form
could I reharden? could you reharden? could he reharden? could we reharden? could you reharden? could they reharden?
V-ing form
could I be rehardening? could you be rehardening? could he be rehardening? could we be rehardening? could you be rehardening? could they be rehardening?
Perfect
could I have rehardened? could you have rehardened? could he have rehardened? could we have rehardened? could you have rehardened? could they have rehardened?
V-ing perfect
could I have been rehardening? could you have been rehardening? could he have been rehardening? could we have been rehardening? could you have been rehardening? could they have been rehardening?
Interro-negative form
Simple form
couldn't I reharden? couldn't you reharden? couldn't he reharden? couldn't we reharden? couldn't you reharden? couldn't they reharden?
V-ing form
couldn't I be rehardening? couldn't you be rehardening? couldn't he be rehardening? couldn't we be rehardening? couldn't you be rehardening? couldn't they be rehardening?
Perfect
couldn't I have rehardened? couldn't you have rehardened? couldn't he have rehardened? couldn't we have rehardened? couldn't you have rehardened? couldn't they have rehardened?
V-ing perfect
couldn't I have been rehardening? couldn't you have been rehardening? couldn't he have been rehardening? couldn't we have been rehardening? couldn't you have been rehardening? couldn't they have been rehardening?