English verb conjugation MUST STIFF

Regular verb: stiff - stiffed - stiffed

Affirmation

Simple form

I must stiff
you must stiff
he must stiff
we must stiff
you must stiff
they must stiff

V-ing form

I must be stiffing
you must be stiffing
he must be stiffing
we must be stiffing
you must be stiffing
they must be stiffing

Perfect

I must have stiffed
you must have stiffed
he must have stiffed
we must have stiffed
you must have stiffed
they must have stiffed

V-ing perfect

I must have been stiffing
you must have been stiffing
he must have been stiffing
we must have been stiffing
you must have been stiffing
they must have been stiffing

Negation

Simple form

I mustn't stiff
you mustn't stiff
he mustn't stiff
we mustn't stiff
you mustn't stiff
they mustn't stiff

V-ing form

I mustn't be stiffing
you mustn't be stiffing
he mustn't be stiffing
we mustn't be stiffing
you mustn't be stiffing
they mustn't be stiffing

Perfect

I mustn't have stiffed
you mustn't have stiffed
he mustn't have stiffed
we mustn't have stiffed
you mustn't have stiffed
they mustn't have stiffed

V-ing perfect

I mustn't have been stiffing
you mustn't have been stiffing
he mustn't have been stiffing
we mustn't have been stiffing
you mustn't have been stiffing
they mustn't have been stiffing

Interrogative form

Simple form

must I stiff?
must you stiff?
must he stiff?
must we stiff?
must you stiff?
must they stiff?

V-ing form

must I be stiffing?
must you be stiffing?
must he be stiffing?
must we be stiffing?
must you be stiffing?
must they be stiffing?

Perfect

must I have stiffed?
must you have stiffed?
must he have stiffed?
must we have stiffed?
must you have stiffed?
must they have stiffed?

V-ing perfect

must I have been stiffing?
must you have been stiffing?
must he have been stiffing?
must we have been stiffing?
must you have been stiffing?
must they have been stiffing?

Interro-negative form

Simple form

mustn't I stiff?
mustn't you stiff?
mustn't he stiff?
mustn't we stiff?
mustn't you stiff?
mustn't they stiff?

V-ing form

mustn't I be stiffing?
mustn't you be stiffing?
mustn't he be stiffing?
mustn't we be stiffing?
mustn't you be stiffing?
mustn't they be stiffing?

Perfect

mustn't I have stiffed?
mustn't you have stiffed?
mustn't he have stiffed?
mustn't we have stiffed?
mustn't you have stiffed?
mustn't they have stiffed?

V-ing perfect

mustn't I have been stiffing?
mustn't you have been stiffing?
mustn't he have been stiffing?
mustn't we have been stiffing?
mustn't you have been stiffing?
mustn't they have been stiffing?

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