English verb conjugation
MUST FAIL FAIL

Regular verb: fail fail - fail failed - fail failed

Warning, this verb may not exist. Conjugation is given as example.

Affirmation

Simple form	V-ing form
I must fail fail you must fail fail he must fail fail we must fail fail you must fail fail they must fail fail	I must be fail failing you must be fail failing he must be fail failing we must be fail failing you must be fail failing they must be fail failing
Perfect	V-ing perfect
I must have fail failed you must have fail failed he must have fail failed we must have fail failed you must have fail failed they must have fail failed	I must have been fail failing you must have been fail failing he must have been fail failing we must have been fail failing you must have been fail failing they must have been fail failing

Negation

Simple form	V-ing form
I mustn't fail fail you mustn't fail fail he mustn't fail fail we mustn't fail fail you mustn't fail fail they mustn't fail fail	I mustn't be fail failing you mustn't be fail failing he mustn't be fail failing we mustn't be fail failing you mustn't be fail failing they mustn't be fail failing
Perfect	V-ing perfect
I mustn't have fail failed you mustn't have fail failed he mustn't have fail failed we mustn't have fail failed you mustn't have fail failed they mustn't have fail failed	I mustn't have been fail failing you mustn't have been fail failing he mustn't have been fail failing we mustn't have been fail failing you mustn't have been fail failing they mustn't have been fail failing

Interrogative form

Simple form	V-ing form
must I fail fail? must you fail fail? must he fail fail? must we fail fail? must you fail fail? must they fail fail?	must I be fail failing? must you be fail failing? must he be fail failing? must we be fail failing? must you be fail failing? must they be fail failing?
Perfect	V-ing perfect
must I have fail failed? must you have fail failed? must he have fail failed? must we have fail failed? must you have fail failed? must they have fail failed?	must I have been fail failing? must you have been fail failing? must he have been fail failing? must we have been fail failing? must you have been fail failing? must they have been fail failing?

Interro-negative form

Simple form	V-ing form
mustn't I fail fail? mustn't you fail fail? mustn't he fail fail? mustn't we fail fail? mustn't you fail fail? mustn't they fail fail?	mustn't I be fail failing? mustn't you be fail failing? mustn't he be fail failing? mustn't we be fail failing? mustn't you be fail failing? mustn't they be fail failing?
Perfect	V-ing perfect
mustn't I have fail failed? mustn't you have fail failed? mustn't he have fail failed? mustn't we have fail failed? mustn't you have fail failed? mustn't they have fail failed?	mustn't I have been fail failing? mustn't you have been fail failing? mustn't he have been fail failing? mustn't we have been fail failing? mustn't you have been fail failing? mustn't they have been fail failing?