English verb conjugation
MUST SIFT

Regular verb: sift - sifted - sifted

Affirmation

Simple form	V-ing form
I must sift you must sift she must sift we must sift you must sift they must sift	I must be sifting you must be sifting she must be sifting we must be sifting you must be sifting they must be sifting
Perfect	V-ing perfect
I must have sifted you must have sifted she must have sifted we must have sifted you must have sifted they must have sifted	I must have been sifting you must have been sifting she must have been sifting we must have been sifting you must have been sifting they must have been sifting

Negation

Simple form	V-ing form
I mustn't sift you mustn't sift she mustn't sift we mustn't sift you mustn't sift they mustn't sift	I mustn't be sifting you mustn't be sifting she mustn't be sifting we mustn't be sifting you mustn't be sifting they mustn't be sifting
Perfect	V-ing perfect
I mustn't have sifted you mustn't have sifted she mustn't have sifted we mustn't have sifted you mustn't have sifted they mustn't have sifted	I mustn't have been sifting you mustn't have been sifting she mustn't have been sifting we mustn't have been sifting you mustn't have been sifting they mustn't have been sifting

Interrogative form

Simple form	V-ing form
must I sift? must you sift? must she sift? must we sift? must you sift? must they sift?	must I be sifting? must you be sifting? must she be sifting? must we be sifting? must you be sifting? must they be sifting?
Perfect	V-ing perfect
must I have sifted? must you have sifted? must she have sifted? must we have sifted? must you have sifted? must they have sifted?	must I have been sifting? must you have been sifting? must she have been sifting? must we have been sifting? must you have been sifting? must they have been sifting?

Interro-negative form

Simple form	V-ing form
mustn't I sift? mustn't you sift? mustn't she sift? mustn't we sift? mustn't you sift? mustn't they sift?	mustn't I be sifting? mustn't you be sifting? mustn't she be sifting? mustn't we be sifting? mustn't you be sifting? mustn't they be sifting?
Perfect	V-ing perfect
mustn't I have sifted? mustn't you have sifted? mustn't she have sifted? mustn't we have sifted? mustn't you have sifted? mustn't they have sifted?	mustn't I have been sifting? mustn't you have been sifting? mustn't she have been sifting? mustn't we have been sifting? mustn't you have been sifting? mustn't they have been sifting?