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