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