I must prefer you must prefer he must prefer we must prefer you must prefer they must prefer
V-ing form
I must be preferring you must be preferring he must be preferring we must be preferring you must be preferring they must be preferring
Perfect
I must have preferred you must have preferred he must have preferred we must have preferred you must have preferred they must have preferred
V-ing perfect
I must have been preferring you must have been preferring he must have been preferring we must have been preferring you must have been preferring they must have been preferring
Negation
Simple form
I must not prefer you must not prefer he must not prefer we must not prefer you must not prefer they must not prefer
V-ing form
I must not be preferring you must not be preferring he must not be preferring we must not be preferring you must not be preferring they must not be preferring
Perfect
I must not have preferred you must not have preferred he must not have preferred we must not have preferred you must not have preferred they must not have preferred
V-ing perfect
I must not have been preferring you must not have been preferring he must not have been preferring we must not have been preferring you must not have been preferring they must not have been preferring
Interrogative form
Simple form
must I prefer? must you prefer? must he prefer? must we prefer? must you prefer? must they prefer?
V-ing form
must I be preferring? must you be preferring? must he be preferring? must we be preferring? must you be preferring? must they be preferring?
Perfect
must I have preferred? must you have preferred? must he have preferred? must we have preferred? must you have preferred? must they have preferred?
V-ing perfect
must I have been preferring? must you have been preferring? must he have been preferring? must we have been preferring? must you have been preferring? must they have been preferring?
Interro-negative form
Simple form
must I not prefer? must you not prefer? must he not prefer? must we not prefer? must you not prefer? must they not prefer?
V-ing form
must I not be preferring? must you not be preferring? must he not be preferring? must we not be preferring? must you not be preferring? must they not be preferring?
Perfect
must I not have preferred? must you not have preferred? must he not have preferred? must we not have preferred? must you not have preferred? must they not have preferred?
V-ing perfect
must I not have been preferring? must you not have been preferring? must he not have been preferring? must we not have been preferring? must you not have been preferring? must they not have been preferring?