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