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