I can bump you can bump he can bump we can bump you can bump they can bump
V-ing form
I can be bumping you can be bumping he can be bumping we can be bumping you can be bumping they can be bumping
Perfect
I can have bumped you can have bumped he can have bumped we can have bumped you can have bumped they can have bumped
V-ing perfect
I can have been bumping you can have been bumping he can have been bumping we can have been bumping you can have been bumping they can have been bumping
Negation
Simple form
I cannot bump you cannot bump he cannot bump we cannot bump you cannot bump they cannot bump
V-ing form
I cannot be bumping you cannot be bumping he cannot be bumping we cannot be bumping you cannot be bumping they cannot be bumping
Perfect
I cannot have bumped you cannot have bumped he cannot have bumped we cannot have bumped you cannot have bumped they cannot have bumped
V-ing perfect
I cannot have been bumping you cannot have been bumping he cannot have been bumping we cannot have been bumping you cannot have been bumping they cannot have been bumping
Interrogative form
Simple form
can I bump? can you bump? can he bump? can we bump? can you bump? can they bump?
V-ing form
can I be bumping? can you be bumping? can he be bumping? can we be bumping? can you be bumping? can they be bumping?
Perfect
can I have bumped? can you have bumped? can he have bumped? can we have bumped? can you have bumped? can they have bumped?
V-ing perfect
can I have been bumping? can you have been bumping? can he have been bumping? can we have been bumping? can you have been bumping? can they have been bumping?
Interro-negative form
Simple form
can I not bump? can you not bump? can he not bump? can we not bump? can you not bump? can they not bump?
V-ing form
can I not be bumping? can you not be bumping? can he not be bumping? can we not be bumping? can you not be bumping? can they not be bumping?
Perfect
can I not have bumped? can you not have bumped? can he not have bumped? can we not have bumped? can you not have bumped? can they not have bumped?
V-ing perfect
can I not have been bumping? can you not have been bumping? can he not have been bumping? can we not have been bumping? can you not have been bumping? can they not have been bumping?