I could brood you could brood he could brood we could brood you could brood they could brood
V-ing form
I could be brooding you could be brooding he could be brooding we could be brooding you could be brooding they could be brooding
Perfect
I could have brooded you could have brooded he could have brooded we could have brooded you could have brooded they could have brooded
V-ing perfect
I could have been brooding you could have been brooding he could have been brooding we could have been brooding you could have been brooding they could have been brooding
Negation
Simple form
I could not brood you could not brood he could not brood we could not brood you could not brood they could not brood
V-ing form
I could not be brooding you could not be brooding he could not be brooding we could not be brooding you could not be brooding they could not be brooding
Perfect
I could not have brooded you could not have brooded he could not have brooded we could not have brooded you could not have brooded they could not have brooded
V-ing perfect
I could not have been brooding you could not have been brooding he could not have been brooding we could not have been brooding you could not have been brooding they could not have been brooding
Interrogative form
Simple form
could I brood? could you brood? could he brood? could we brood? could you brood? could they brood?
V-ing form
could I be brooding? could you be brooding? could he be brooding? could we be brooding? could you be brooding? could they be brooding?
Perfect
could I have brooded? could you have brooded? could he have brooded? could we have brooded? could you have brooded? could they have brooded?
V-ing perfect
could I have been brooding? could you have been brooding? could he have been brooding? could we have been brooding? could you have been brooding? could they have been brooding?
Interro-negative form
Simple form
could I not brood? could you not brood? could he not brood? could we not brood? could you not brood? could they not brood?
V-ing form
could I not be brooding? could you not be brooding? could he not be brooding? could we not be brooding? could you not be brooding? could they not be brooding?
Perfect
could I not have brooded? could you not have brooded? could he not have brooded? could we not have brooded? could you not have brooded? could they not have brooded?
V-ing perfect
could I not have been brooding? could you not have been brooding? could he not have been brooding? could we not have been brooding? could you not have been brooding? could they not have been brooding?