I could restraighten you could restraighten she could restraighten we could restraighten you could restraighten they could restraighten
V-ing form
I could be restraightening you could be restraightening she could be restraightening we could be restraightening you could be restraightening they could be restraightening
Perfect
I could have restraightened you could have restraightened she could have restraightened we could have restraightened you could have restraightened they could have restraightened
V-ing perfect
I could have been restraightening you could have been restraightening she could have been restraightening we could have been restraightening you could have been restraightening they could have been restraightening
Negation
Simple form
I couldn't restraighten you couldn't restraighten she couldn't restraighten we couldn't restraighten you couldn't restraighten they couldn't restraighten
V-ing form
I couldn't be restraightening you couldn't be restraightening she couldn't be restraightening we couldn't be restraightening you couldn't be restraightening they couldn't be restraightening
Perfect
I couldn't have restraightened you couldn't have restraightened she couldn't have restraightened we couldn't have restraightened you couldn't have restraightened they couldn't have restraightened
V-ing perfect
I couldn't have been restraightening you couldn't have been restraightening she couldn't have been restraightening we couldn't have been restraightening you couldn't have been restraightening they couldn't have been restraightening
Interrogative form
Simple form
could I restraighten? could you restraighten? could she restraighten? could we restraighten? could you restraighten? could they restraighten?
V-ing form
could I be restraightening? could you be restraightening? could she be restraightening? could we be restraightening? could you be restraightening? could they be restraightening?
Perfect
could I have restraightened? could you have restraightened? could she have restraightened? could we have restraightened? could you have restraightened? could they have restraightened?
V-ing perfect
could I have been restraightening? could you have been restraightening? could she have been restraightening? could we have been restraightening? could you have been restraightening? could they have been restraightening?
Interro-negative form
Simple form
couldn't I restraighten? couldn't you restraighten? couldn't she restraighten? couldn't we restraighten? couldn't you restraighten? couldn't they restraighten?
V-ing form
couldn't I be restraightening? couldn't you be restraightening? couldn't she be restraightening? couldn't we be restraightening? couldn't you be restraightening? couldn't they be restraightening?
Perfect
couldn't I have restraightened? couldn't you have restraightened? couldn't she have restraightened? couldn't we have restraightened? couldn't you have restraightened? couldn't they have restraightened?
V-ing perfect
couldn't I have been restraightening? couldn't you have been restraightening? couldn't she have been restraightening? couldn't we have been restraightening? couldn't you have been restraightening? couldn't they have been restraightening?