I could top you could top she could top we could top you could top they could top
V-ing form
I could be topping you could be topping she could be topping we could be topping you could be topping they could be topping
Perfect
I could have topped you could have topped she 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 she 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 she 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 she 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 she 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 she 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 she top? could we top? could you top? could they top?
V-ing form
could I be topping? could you be topping? could she be topping? could we be topping? could you be topping? could they be topping?
Perfect
could I have topped? could you have topped? could she 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 she 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 she 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 she 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 she 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 she have been topping? couldn't we have been topping? couldn't you have been topping? couldn't they have been topping?