I can block you can block she can block we can block you can block they can block
V-ing form
I can be blocking you can be blocking she can be blocking we can be blocking you can be blocking they can be blocking
Perfect
I can have blocked you can have blocked she can have blocked we can have blocked you can have blocked they can have blocked
V-ing perfect
I can have been blocking you can have been blocking she can have been blocking we can have been blocking you can have been blocking they can have been blocking
Negation
Simple form
I cannot block you cannot block she cannot block we cannot block you cannot block they cannot block
V-ing form
I cannot be blocking you cannot be blocking she cannot be blocking we cannot be blocking you cannot be blocking they cannot be blocking
Perfect
I cannot have blocked you cannot have blocked she cannot have blocked we cannot have blocked you cannot have blocked they cannot have blocked
V-ing perfect
I cannot have been blocking you cannot have been blocking she cannot have been blocking we cannot have been blocking you cannot have been blocking they cannot have been blocking
Interrogative form
Simple form
can I block? can you block? can she block? can we block? can you block? can they block?
V-ing form
can I be blocking? can you be blocking? can she be blocking? can we be blocking? can you be blocking? can they be blocking?
Perfect
can I have blocked? can you have blocked? can she have blocked? can we have blocked? can you have blocked? can they have blocked?
V-ing perfect
can I have been blocking? can you have been blocking? can she have been blocking? can we have been blocking? can you have been blocking? can they have been blocking?
Interro-negative form
Simple form
can I not block? can you not block? can she not block? can we not block? can you not block? can they not block?
V-ing form
can I not be blocking? can you not be blocking? can she not be blocking? can we not be blocking? can you not be blocking? can they not be blocking?
Perfect
can I not have blocked? can you not have blocked? can she not have blocked? can we not have blocked? can you not have blocked? can they not have blocked?
V-ing perfect
can I not have been blocking? can you not have been blocking? can she not have been blocking? can we not have been blocking? can you not have been blocking? can they not have been blocking?