English verb conjugation
MUST SKIRR

Regular verb: skirr - skirred - skirred

Affirmation

Simple form	V-ing form
I must skirr you must skirr he must skirr we must skirr you must skirr they must skirr	I must be skirring you must be skirring he must be skirring we must be skirring you must be skirring they must be skirring
Perfect	V-ing perfect
I must have skirred you must have skirred he must have skirred we must have skirred you must have skirred they must have skirred	I must have been skirring you must have been skirring he must have been skirring we must have been skirring you must have been skirring they must have been skirring

Negation

Simple form	V-ing form
I mustn't skirr you mustn't skirr he mustn't skirr we mustn't skirr you mustn't skirr they mustn't skirr	I mustn't be skirring you mustn't be skirring he mustn't be skirring we mustn't be skirring you mustn't be skirring they mustn't be skirring
Perfect	V-ing perfect
I mustn't have skirred you mustn't have skirred he mustn't have skirred we mustn't have skirred you mustn't have skirred they mustn't have skirred	I mustn't have been skirring you mustn't have been skirring he mustn't have been skirring we mustn't have been skirring you mustn't have been skirring they mustn't have been skirring

Interrogative form

Simple form	V-ing form
must I skirr? must you skirr? must he skirr? must we skirr? must you skirr? must they skirr?	must I be skirring? must you be skirring? must he be skirring? must we be skirring? must you be skirring? must they be skirring?
Perfect	V-ing perfect
must I have skirred? must you have skirred? must he have skirred? must we have skirred? must you have skirred? must they have skirred?	must I have been skirring? must you have been skirring? must he have been skirring? must we have been skirring? must you have been skirring? must they have been skirring?

Interro-negative form

Simple form	V-ing form
mustn't I skirr? mustn't you skirr? mustn't he skirr? mustn't we skirr? mustn't you skirr? mustn't they skirr?	mustn't I be skirring? mustn't you be skirring? mustn't he be skirring? mustn't we be skirring? mustn't you be skirring? mustn't they be skirring?
Perfect	V-ing perfect
mustn't I have skirred? mustn't you have skirred? mustn't he have skirred? mustn't we have skirred? mustn't you have skirred? mustn't they have skirred?	mustn't I have been skirring? mustn't you have been skirring? mustn't he have been skirring? mustn't we have been skirring? mustn't you have been skirring? mustn't they have been skirring?