I can postpone you can postpone he can postpone we can postpone you can postpone they can postpone
V-ing form
I can be postponing you can be postponing he can be postponing we can be postponing you can be postponing they can be postponing
Perfect
I can have postponed you can have postponed he can have postponed we can have postponed you can have postponed they can have postponed
V-ing perfect
I can have been postponing you can have been postponing he can have been postponing we can have been postponing you can have been postponing they can have been postponing
Negation
Simple form
I cannot postpone you cannot postpone he cannot postpone we cannot postpone you cannot postpone they cannot postpone
V-ing form
I cannot be postponing you cannot be postponing he cannot be postponing we cannot be postponing you cannot be postponing they cannot be postponing
Perfect
I cannot have postponed you cannot have postponed he cannot have postponed we cannot have postponed you cannot have postponed they cannot have postponed
V-ing perfect
I cannot have been postponing you cannot have been postponing he cannot have been postponing we cannot have been postponing you cannot have been postponing they cannot have been postponing
Interrogative form
Simple form
can I postpone? can you postpone? can he postpone? can we postpone? can you postpone? can they postpone?
V-ing form
can I be postponing? can you be postponing? can he be postponing? can we be postponing? can you be postponing? can they be postponing?
Perfect
can I have postponed? can you have postponed? can he have postponed? can we have postponed? can you have postponed? can they have postponed?
V-ing perfect
can I have been postponing? can you have been postponing? can he have been postponing? can we have been postponing? can you have been postponing? can they have been postponing?
Interro-negative form
Simple form
can I not postpone? can you not postpone? can he not postpone? can we not postpone? can you not postpone? can they not postpone?
V-ing form
can I not be postponing? can you not be postponing? can he not be postponing? can we not be postponing? can you not be postponing? can they not be postponing?
Perfect
can I not have postponed? can you not have postponed? can he not have postponed? can we not have postponed? can you not have postponed? can they not have postponed?
V-ing perfect
can I not have been postponing? can you not have been postponing? can he not have been postponing? can we not have been postponing? can you not have been postponing? can they not have been postponing?