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