must sift
Verbo regular: sift - sifted- sifted

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must sift
you must sift
he must sift
we must sift
you must sift
they must sift 	I must be sifting
you must be sifting
he must be sifting
we must be sifting
you must be sifting
they must be sifting	I must have sifted
you must have sifted
he 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
he must have been sifting
we must have been sifting
you must have been sifting
they must have been sifting	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not sift
you must not sift
he must not sift
we must not sift
you must not sift
they must not sift 	I must not be sifting
you must not be sifting
he must not be sifting
we must not be sifting
you must not be sifting
they must not be sifting	I must not have sifted
you must not have sifted
he must not have sifted
we must not have sifted
you must not have sifted
they must not have sifted	I must not have been sifting
you must not have been sifting
he must not have been sifting
we must not have been sifting
you must not have been sifting
they must not have been sifting	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I sift?
must you sift?
must he sift?
must we sift?
must you sift?
must they sift? 	must I be sifting?
must you be sifting?
must he be sifting?
must we be sifting?
must you be sifting?
must they be sifting? 	must I have sifted?
must you have sifted?
must he 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 he have been sifting?
must we have been sifting?
must you have been sifting?
must they have been sifting? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not sift?
must you not sift?
must he not sift?
must we not sift?
must you not sift?
must they not sift? 	must I not be sifting?
must you not be sifting?
must he not be sifting?
must we not be sifting?
must you not be sifting?
must they not be sifting? 	must I not have sifted?
must you not have sifted?
must he not have sifted?
must we not have sifted?
must you not have sifted?
must they not have sifted? 	must I not have been sifting?
must you not have been sifting?
must he not have been sifting?
must we not have been sifting?
must you not have been sifting?
must they not have been sifting?