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 mustn't birdie you mustn't birdie he mustn't birdie we mustn't birdie you mustn't birdie they mustn't birdie
V-ing form
I mustn't be birdying you mustn't be birdying he mustn't be birdying we mustn't be birdying you mustn't be birdying they mustn't be birdying
Perfect
I mustn't have birdied you mustn't have birdied he mustn't have birdied we mustn't have birdied you mustn't have birdied they mustn't have birdied
V-ing perfect
I mustn't have been birdying you mustn't have been birdying he mustn't have been birdying we mustn't have been birdying you mustn't have been birdying they mustn't 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
mustn't I birdie? mustn't you birdie? mustn't he birdie? mustn't we birdie? mustn't you birdie? mustn't they birdie?
V-ing form
mustn't I be birdying? mustn't you be birdying? mustn't he be birdying? mustn't we be birdying? mustn't you be birdying? mustn't they be birdying?
Perfect
mustn't I have birdied? mustn't you have birdied? mustn't he have birdied? mustn't we have birdied? mustn't you have birdied? mustn't they have birdied?
V-ing perfect
mustn't I have been birdying? mustn't you have been birdying? mustn't he have been birdying? mustn't we have been birdying? mustn't you have been birdying? mustn't they have been birdying?