I can subscribe you can subscribe he can subscribe we can subscribe you can subscribe they can subscribe
V-ing form
I can be subscribing you can be subscribing he can be subscribing we can be subscribing you can be subscribing they can be subscribing
Perfect
I can have subscribed you can have subscribed he can have subscribed we can have subscribed you can have subscribed they can have subscribed
V-ing perfect
I can have been subscribing you can have been subscribing he can have been subscribing we can have been subscribing you can have been subscribing they can have been subscribing
Negation
Simple form
I can't subscribe you can't subscribe he can't subscribe we can't subscribe you can't subscribe they can't subscribe
V-ing form
I can't be subscribing you can't be subscribing he can't be subscribing we can't be subscribing you can't be subscribing they can't be subscribing
Perfect
I can't have subscribed you can't have subscribed he can't have subscribed we can't have subscribed you can't have subscribed they can't have subscribed
V-ing perfect
I can't have been subscribing you can't have been subscribing he can't have been subscribing we can't have been subscribing you can't have been subscribing they can't have been subscribing
Interrogative form
Simple form
can I subscribe? can you subscribe? can he subscribe? can we subscribe? can you subscribe? can they subscribe?
V-ing form
can I be subscribing? can you be subscribing? can he be subscribing? can we be subscribing? can you be subscribing? can they be subscribing?
Perfect
can I have subscribed? can you have subscribed? can he have subscribed? can we have subscribed? can you have subscribed? can they have subscribed?
V-ing perfect
can I have been subscribing? can you have been subscribing? can he have been subscribing? can we have been subscribing? can you have been subscribing? can they have been subscribing?
Interro-negative form
Simple form
can't I subscribe? can't you subscribe? can't he subscribe? can't we subscribe? can't you subscribe? can't they subscribe?
V-ing form
can't I be subscribing? can't you be subscribing? can't he be subscribing? can't we be subscribing? can't you be subscribing? can't they be subscribing?
Perfect
can't I have subscribed? can't you have subscribed? can't he have subscribed? can't we have subscribed? can't you have subscribed? can't they have subscribed?
V-ing perfect
can't I have been subscribing? can't you have been subscribing? can't he have been subscribing? can't we have been subscribing? can't you have been subscribing? can't they have been subscribing?