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