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 can't postpone you can't postpone he can't postpone we can't postpone you can't postpone they can't postpone
V-ing form
I can't be postponing you can't be postponing he can't be postponing we can't be postponing you can't be postponing they can't be postponing
Perfect
I can't have postponed you can't have postponed he can't have postponed we can't have postponed you can't have postponed they can't have postponed
V-ing perfect
I can't have been postponing you can't have been postponing he can't have been postponing we can't have been postponing you can't have been postponing they can't 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't I postpone? can't you postpone? can't he postpone? can't we postpone? can't you postpone? can't they postpone?
V-ing form
can't I be postponing? can't you be postponing? can't he be postponing? can't we be postponing? can't you be postponing? can't they be postponing?
Perfect
can't I have postponed? can't you have postponed? can't he have postponed? can't we have postponed? can't you have postponed? can't they have postponed?
V-ing perfect
can't I have been postponing? can't you have been postponing? can't he have been postponing? can't we have been postponing? can't you have been postponing? can't they have been postponing?