I can block you can block he can block we can block you can block they can block
V-ing form
I can be blocking you can be blocking he can be blocking we can be blocking you can be blocking they can be blocking
Perfect
I can have blocked you can have blocked he 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 he can have been blocking we can have been blocking you can have been blocking they can have been blocking
Negation
Simple form
I can't block you can't block he can't block we can't block you can't block they can't block
V-ing form
I can't be blocking you can't be blocking he can't be blocking we can't be blocking you can't be blocking they can't be blocking
Perfect
I can't have blocked you can't have blocked he can't have blocked we can't have blocked you can't have blocked they can't have blocked
V-ing perfect
I can't have been blocking you can't have been blocking he can't have been blocking we can't have been blocking you can't have been blocking they can't have been blocking
Interrogative form
Simple form
can I block? can you block? can he block? can we block? can you block? can they block?
V-ing form
can I be blocking? can you be blocking? can he be blocking? can we be blocking? can you be blocking? can they be blocking?
Perfect
can I have blocked? can you have blocked? can he 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 he have been blocking? can we have been blocking? can you have been blocking? can they have been blocking?
Interro-negative form
Simple form
can't I block? can't you block? can't he block? can't we block? can't you block? can't they block?
V-ing form
can't I be blocking? can't you be blocking? can't he be blocking? can't we be blocking? can't you be blocking? can't they be blocking?
Perfect
can't I have blocked? can't you have blocked? can't he have blocked? can't we have blocked? can't you have blocked? can't they have blocked?
V-ing perfect
can't I have been blocking? can't you have been blocking? can't he have been blocking? can't we have been blocking? can't you have been blocking? can't they have been blocking?