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 must not whirr you must not whirr he must not whirr we must not whirr you must not whirr they must not whirr	I must not be whirring you must not be whirring he must not be whirring we must not be whirring you must not be whirring they must not be whirring
Perfect	V-ing perfect
I must not have whirred you must not have whirred he must not have whirred we must not have whirred you must not have whirred they must not have whirred	I must not have been whirring you must not have been whirring he must not have been whirring we must not have been whirring you must not have been whirring they must not 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
must I not whirr? must you not whirr? must he not whirr? must we not whirr? must you not whirr? must they not whirr?	must I not be whirring? must you not be whirring? must he not be whirring? must we not be whirring? must you not be whirring? must they not be whirring?
Perfect	V-ing perfect
must I not have whirred? must you not have whirred? must he not have whirred? must we not have whirred? must you not have whirred? must they not have whirred?	must I not have been whirring? must you not have been whirring? must he not have been whirring? must we not have been whirring? must you not have been whirring? must they not have been whirring?