I could pack you could pack he could pack we could pack you could pack they could pack
V-ing form
I could be packing you could be packing he could be packing we could be packing you could be packing they could be packing
Perfect
I could have packed you could have packed he could have packed we could have packed you could have packed they could have packed
V-ing perfect
I could have been packing you could have been packing he could have been packing we could have been packing you could have been packing they could have been packing
Negation
Simple form
I couldn't pack you couldn't pack he couldn't pack we couldn't pack you couldn't pack they couldn't pack
V-ing form
I couldn't be packing you couldn't be packing he couldn't be packing we couldn't be packing you couldn't be packing they couldn't be packing
Perfect
I couldn't have packed you couldn't have packed he couldn't have packed we couldn't have packed you couldn't have packed they couldn't have packed
V-ing perfect
I couldn't have been packing you couldn't have been packing he couldn't have been packing we couldn't have been packing you couldn't have been packing they couldn't have been packing
Interrogative form
Simple form
could I pack? could you pack? could he pack? could we pack? could you pack? could they pack?
V-ing form
could I be packing? could you be packing? could he be packing? could we be packing? could you be packing? could they be packing?
Perfect
could I have packed? could you have packed? could he have packed? could we have packed? could you have packed? could they have packed?
V-ing perfect
could I have been packing? could you have been packing? could he have been packing? could we have been packing? could you have been packing? could they have been packing?
Interro-negative form
Simple form
couldn't I pack? couldn't you pack? couldn't he pack? couldn't we pack? couldn't you pack? couldn't they pack?
V-ing form
couldn't I be packing? couldn't you be packing? couldn't he be packing? couldn't we be packing? couldn't you be packing? couldn't they be packing?
Perfect
couldn't I have packed? couldn't you have packed? couldn't he have packed? couldn't we have packed? couldn't you have packed? couldn't they have packed?
V-ing perfect
couldn't I have been packing? couldn't you have been packing? couldn't he have been packing? couldn't we have been packing? couldn't you have been packing? couldn't they have been packing?