I can pack you can pack he can pack we can pack you can pack they can pack
V-ing form
I can be packing you can be packing he can be packing we can be packing you can be packing they can be packing
Perfect
I can have packed you can have packed he can have packed we can have packed you can have packed they can have packed
V-ing perfect
I can have been packing you can have been packing he can have been packing we can have been packing you can have been packing they can have been packing
Negation
Simple form
I cannot pack you cannot pack he cannot pack we cannot pack you cannot pack they cannot pack
V-ing form
I cannot be packing you cannot be packing he cannot be packing we cannot be packing you cannot be packing they cannot be packing
Perfect
I cannot have packed you cannot have packed he cannot have packed we cannot have packed you cannot have packed they cannot have packed
V-ing perfect
I cannot have been packing you cannot have been packing he cannot have been packing we cannot have been packing you cannot have been packing they cannot have been packing
Interrogative form
Simple form
can I pack? can you pack? can he pack? can we pack? can you pack? can they pack?
V-ing form
can I be packing? can you be packing? can he be packing? can we be packing? can you be packing? can they be packing?
Perfect
can I have packed? can you have packed? can he have packed? can we have packed? can you have packed? can they have packed?
V-ing perfect
can I have been packing? can you have been packing? can he have been packing? can we have been packing? can you have been packing? can they have been packing?
Interro-negative form
Simple form
can I not pack? can you not pack? can he not pack? can we not pack? can you not pack? can they not pack?
V-ing form
can I not be packing? can you not be packing? can he not be packing? can we not be packing? can you not be packing? can they not be packing?
Perfect
can I not have packed? can you not have packed? can he not have packed? can we not have packed? can you not have packed? can they not have packed?
V-ing perfect
can I not have been packing? can you not have been packing? can he not have been packing? can we not have been packing? can you not have been packing? can they not have been packing?