I could brake you could brake he could brake we could brake you could brake they could brake
V-ing form
I could be braking you could be braking he could be braking we could be braking you could be braking they could be braking
Perfect
I could have braked you could have braked he 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 he 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 he 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 he 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 he 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 he 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 he brake? could we brake? could you brake? could they brake?
V-ing form
could I be braking? could you be braking? could he be braking? could we be braking? could you be braking? could they be braking?
Perfect
could I have braked? could you have braked? could he 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 he 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 he 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 he 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 he 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 he have been braking? couldn't we have been braking? couldn't you have been braking? couldn't they have been braking?