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 cannot subscribe you cannot subscribe he cannot subscribe we cannot subscribe you cannot subscribe they cannot subscribe
V-ing form
I cannot be subscribing you cannot be subscribing he cannot be subscribing we cannot be subscribing you cannot be subscribing they cannot be subscribing
Perfect
I cannot have subscribed you cannot have subscribed he cannot have subscribed we cannot have subscribed you cannot have subscribed they cannot have subscribed
V-ing perfect
I cannot have been subscribing you cannot have been subscribing he cannot have been subscribing we cannot have been subscribing you cannot have been subscribing they cannot 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 I not subscribe? can you not subscribe? can he not subscribe? can we not subscribe? can you not subscribe? can they not subscribe?
V-ing form
can I not be subscribing? can you not be subscribing? can he not be subscribing? can we not be subscribing? can you not be subscribing? can they not be subscribing?
Perfect
can I not have subscribed? can you not have subscribed? can he not have subscribed? can we not have subscribed? can you not have subscribed? can they not have subscribed?
V-ing perfect
can I not have been subscribing? can you not have been subscribing? can he not have been subscribing? can we not have been subscribing? can you not have been subscribing? can they not have been subscribing?