I could stock you could stock she could stock we could stock you could stock they could stock
V-ing form
I could be stocking you could be stocking she could be stocking we could be stocking you could be stocking they could be stocking
Perfect
I could have stocked you could have stocked she could have stocked we could have stocked you could have stocked they could have stocked
V-ing perfect
I could have been stocking you could have been stocking she could have been stocking we could have been stocking you could have been stocking they could have been stocking
Negation
Simple form
I could not stock you could not stock she could not stock we could not stock you could not stock they could not stock
V-ing form
I could not be stocking you could not be stocking she could not be stocking we could not be stocking you could not be stocking they could not be stocking
Perfect
I could not have stocked you could not have stocked she could not have stocked we could not have stocked you could not have stocked they could not have stocked
V-ing perfect
I could not have been stocking you could not have been stocking she could not have been stocking we could not have been stocking you could not have been stocking they could not have been stocking
Interrogative form
Simple form
could I stock? could you stock? could she stock? could we stock? could you stock? could they stock?
V-ing form
could I be stocking? could you be stocking? could she be stocking? could we be stocking? could you be stocking? could they be stocking?
Perfect
could I have stocked? could you have stocked? could she have stocked? could we have stocked? could you have stocked? could they have stocked?
V-ing perfect
could I have been stocking? could you have been stocking? could she have been stocking? could we have been stocking? could you have been stocking? could they have been stocking?
Interro-negative form
Simple form
could I not stock? could you not stock? could she not stock? could we not stock? could you not stock? could they not stock?
V-ing form
could I not be stocking? could you not be stocking? could she not be stocking? could we not be stocking? could you not be stocking? could they not be stocking?
Perfect
could I not have stocked? could you not have stocked? could she not have stocked? could we not have stocked? could you not have stocked? could they not have stocked?
V-ing perfect
could I not have been stocking? could you not have been stocking? could she not have been stocking? could we not have been stocking? could you not have been stocking? could they not have been stocking?