English verb conjugation MUST BIFF

Regular verb: biff - biffed - biffed

Affirmation

Simple form

I must biff
you must biff
he must biff
we must biff
you must biff
they must biff

V-ing form

I must be biffing
you must be biffing
he must be biffing
we must be biffing
you must be biffing
they must be biffing

Perfect

I must have biffed
you must have biffed
he must have biffed
we must have biffed
you must have biffed
they must have biffed

V-ing perfect

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

Negation

Simple form

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

V-ing form

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

Perfect

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

V-ing perfect

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

Interrogative form

Simple form

must I biff?
must you biff?
must he biff?
must we biff?
must you biff?
must they biff?

V-ing form

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

Perfect

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

V-ing perfect

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

Interro-negative form

Simple form

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

V-ing form

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

Perfect

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

V-ing perfect

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

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