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