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