I could stock you could stock he could stock we could stock you could stock they could stock
V-ing form
I could be stocking you could be stocking he could be stocking we could be stocking you could be stocking they could be stocking
Perfect
I could have stocked you could have stocked he 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 he 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 he 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 he 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 he 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 he 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 he stock? could we stock? could you stock? could they stock?
V-ing form
could I be stocking? could you be stocking? could he be stocking? could we be stocking? could you be stocking? could they be stocking?
Perfect
could I have stocked? could you have stocked? could he 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 he 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 he 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 he 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 he 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 he not have been stocking? could we not have been stocking? could you not have been stocking? could they not have been stocking?