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