English verb conjugation
MUST WHIRR

Regular verb: whirr - whirred - whirred

Affirmation

Simple form	V-ing form
I must whirr you must whirr he must whirr we must whirr you must whirr they must whirr	I must be whirring you must be whirring he must be whirring we must be whirring you must be whirring they must be whirring
Perfect	V-ing perfect
I must have whirred you must have whirred he must have whirred we must have whirred you must have whirred they must have whirred	I must have been whirring you must have been whirring he must have been whirring we must have been whirring you must have been whirring they must have been whirring

Negation

Simple form	V-ing form
I mustn't whirr you mustn't whirr he mustn't whirr we mustn't whirr you mustn't whirr they mustn't whirr	I mustn't be whirring you mustn't be whirring he mustn't be whirring we mustn't be whirring you mustn't be whirring they mustn't be whirring
Perfect	V-ing perfect
I mustn't have whirred you mustn't have whirred he mustn't have whirred we mustn't have whirred you mustn't have whirred they mustn't have whirred	I mustn't have been whirring you mustn't have been whirring he mustn't have been whirring we mustn't have been whirring you mustn't have been whirring they mustn't have been whirring

Interrogative form

Simple form	V-ing form
must I whirr? must you whirr? must he whirr? must we whirr? must you whirr? must they whirr?	must I be whirring? must you be whirring? must he be whirring? must we be whirring? must you be whirring? must they be whirring?
Perfect	V-ing perfect
must I have whirred? must you have whirred? must he have whirred? must we have whirred? must you have whirred? must they have whirred?	must I have been whirring? must you have been whirring? must he have been whirring? must we have been whirring? must you have been whirring? must they have been whirring?

Interro-negative form

Simple form	V-ing form
mustn't I whirr? mustn't you whirr? mustn't he whirr? mustn't we whirr? mustn't you whirr? mustn't they whirr?	mustn't I be whirring? mustn't you be whirring? mustn't he be whirring? mustn't we be whirring? mustn't you be whirring? mustn't they be whirring?
Perfect	V-ing perfect
mustn't I have whirred? mustn't you have whirred? mustn't he have whirred? mustn't we have whirred? mustn't you have whirred? mustn't they have whirred?	mustn't I have been whirring? mustn't you have been whirring? mustn't he have been whirring? mustn't we have been whirring? mustn't you have been whirring? mustn't they have been whirring?