I must birdie you must birdie he must birdie we must birdie you must birdie they must birdie
V-ing form
I must be birdying you must be birdying he must be birdying we must be birdying you must be birdying they must be birdying
Perfect
I must have birdied you must have birdied he must have birdied we must have birdied you must have birdied they must have birdied
V-ing perfect
I must have been birdying you must have been birdying he must have been birdying we must have been birdying you must have been birdying they must have been birdying
Negation
Simple form
I must not birdie you must not birdie he must not birdie we must not birdie you must not birdie they must not birdie
V-ing form
I must not be birdying you must not be birdying he must not be birdying we must not be birdying you must not be birdying they must not be birdying
Perfect
I must not have birdied you must not have birdied he must not have birdied we must not have birdied you must not have birdied they must not have birdied
V-ing perfect
I must not have been birdying you must not have been birdying he must not have been birdying we must not have been birdying you must not have been birdying they must not have been birdying
Interrogative form
Simple form
must I birdie? must you birdie? must he birdie? must we birdie? must you birdie? must they birdie?
V-ing form
must I be birdying? must you be birdying? must he be birdying? must we be birdying? must you be birdying? must they be birdying?
Perfect
must I have birdied? must you have birdied? must he have birdied? must we have birdied? must you have birdied? must they have birdied?
V-ing perfect
must I have been birdying? must you have been birdying? must he have been birdying? must we have been birdying? must you have been birdying? must they have been birdying?
Interro-negative form
Simple form
must I not birdie? must you not birdie? must he not birdie? must we not birdie? must you not birdie? must they not birdie?
V-ing form
must I not be birdying? must you not be birdying? must he not be birdying? must we not be birdying? must you not be birdying? must they not be birdying?
Perfect
must I not have birdied? must you not have birdied? must he not have birdied? must we not have birdied? must you not have birdied? must they not have birdied?
V-ing perfect
must I not have been birdying? must you not have been birdying? must he not have been birdying? must we not have been birdying? must you not have been birdying? must they not have been birdying?