English verb conjugation
MUST BIRCH

Regular verb: birch - birched - birched

Affirmation

Simple form	V-ing form
I must birch you must birch he must birch we must birch you must birch they must birch	I must be birching you must be birching he must be birching we must be birching you must be birching they must be birching
Perfect	V-ing perfect
I must have birched you must have birched he must have birched we must have birched you must have birched they must have birched	I must have been birching you must have been birching he must have been birching we must have been birching you must have been birching they must have been birching

Negation

Simple form	V-ing form
I mustn't birch you mustn't birch he mustn't birch we mustn't birch you mustn't birch they mustn't birch	I mustn't be birching you mustn't be birching he mustn't be birching we mustn't be birching you mustn't be birching they mustn't be birching
Perfect	V-ing perfect
I mustn't have birched you mustn't have birched he mustn't have birched we mustn't have birched you mustn't have birched they mustn't have birched	I mustn't have been birching you mustn't have been birching he mustn't have been birching we mustn't have been birching you mustn't have been birching they mustn't have been birching

Interrogative form

Simple form	V-ing form
must I birch? must you birch? must he birch? must we birch? must you birch? must they birch?	must I be birching? must you be birching? must he be birching? must we be birching? must you be birching? must they be birching?
Perfect	V-ing perfect
must I have birched? must you have birched? must he have birched? must we have birched? must you have birched? must they have birched?	must I have been birching? must you have been birching? must he have been birching? must we have been birching? must you have been birching? must they have been birching?

Interro-negative form

Simple form	V-ing form
mustn't I birch? mustn't you birch? mustn't he birch? mustn't we birch? mustn't you birch? mustn't they birch?	mustn't I be birching? mustn't you be birching? mustn't he be birching? mustn't we be birching? mustn't you be birching? mustn't they be birching?
Perfect	V-ing perfect
mustn't I have birched? mustn't you have birched? mustn't he have birched? mustn't we have birched? mustn't you have birched? mustn't they have birched?	mustn't I have been birching? mustn't you have been birching? mustn't he have been birching? mustn't we have been birching? mustn't you have been birching? mustn't they have been birching?