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