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