I could place you could place she could place we could place you could place they could place
V-ing form
I could be placing you could be placing she could be placing we could be placing you could be placing they could be placing
Perfect
I could have placed you could have placed she could have placed we could have placed you could have placed they could have placed
V-ing perfect
I could have been placing you could have been placing she could have been placing we could have been placing you could have been placing they could have been placing
Negation
Simple form
I couldn't place you couldn't place she couldn't place we couldn't place you couldn't place they couldn't place
V-ing form
I couldn't be placing you couldn't be placing she couldn't be placing we couldn't be placing you couldn't be placing they couldn't be placing
Perfect
I couldn't have placed you couldn't have placed she couldn't have placed we couldn't have placed you couldn't have placed they couldn't have placed
V-ing perfect
I couldn't have been placing you couldn't have been placing she couldn't have been placing we couldn't have been placing you couldn't have been placing they couldn't have been placing
Interrogative form
Simple form
could I place? could you place? could she place? could we place? could you place? could they place?
V-ing form
could I be placing? could you be placing? could she be placing? could we be placing? could you be placing? could they be placing?
Perfect
could I have placed? could you have placed? could she have placed? could we have placed? could you have placed? could they have placed?
V-ing perfect
could I have been placing? could you have been placing? could she have been placing? could we have been placing? could you have been placing? could they have been placing?
Interro-negative form
Simple form
couldn't I place? couldn't you place? couldn't she place? couldn't we place? couldn't you place? couldn't they place?
V-ing form
couldn't I be placing? couldn't you be placing? couldn't she be placing? couldn't we be placing? couldn't you be placing? couldn't they be placing?
Perfect
couldn't I have placed? couldn't you have placed? couldn't she have placed? couldn't we have placed? couldn't you have placed? couldn't they have placed?
V-ing perfect
couldn't I have been placing? couldn't you have been placing? couldn't she have been placing? couldn't we have been placing? couldn't you have been placing? couldn't they have been placing?