I'd be sifting you'd be sifting he'd be sifting we'd be sifting you'd be sifting they'd be sifting
Perfect
I should've sifted you should've sifted he should've sifted we should've sifted you should've sifted they should've sifted
V-ing perfect
I should've been sifting you should've been sifting he should've been sifting we should've been sifting you should've been sifting they should've been sifting
Negation
Simple form
I shouldn't sift you shouldn't sift he shouldn't sift we shouldn't sift you shouldn't sift they shouldn't sift
V-ing form
I shouldn't be sifting you shouldn't be sifting he shouldn't be sifting we shouldn't be sifting you shouldn't be sifting they shouldn't be sifting
Perfect
I shouldn't have sifted you shouldn't have sifted he shouldn't have sifted we shouldn't have sifted you shouldn't have sifted they shouldn't have sifted
V-ing perfect
I shouldn't have been sifting you shouldn't have been sifting he shouldn't have been sifting we shouldn't have been sifting you shouldn't have been sifting they shouldn't have been sifting
Interrogative form
Simple form
should I sift? should you sift? should he sift? should we sift? should you sift? should they sift?
V-ing form
should I be sifting? should you be sifting? should he be sifting? should we be sifting? should you be sifting? should they be sifting?
Perfect
should I have sifted? should you have sifted? should he have sifted? should we have sifted? should you have sifted? should they have sifted?
V-ing perfect
should I have been sifting? should you have been sifting? should he have been sifting? should we have been sifting? should you have been sifting? should they have been sifting?
Interro-negative form
Simple form
shouldn't I sift? shouldn't you sift? shouldn't he sift? shouldn't we sift? shouldn't you sift? shouldn't they sift?
V-ing form
shouldn't I be sifting? shouldn't you be sifting? shouldn't he be sifting? shouldn't we be sifting? shouldn't you be sifting? shouldn't they be sifting?
Perfect
shouldn't I have sifted? shouldn't you have sifted? shouldn't he have sifted? shouldn't we have sifted? shouldn't you have sifted? shouldn't they have sifted?
V-ing perfect
shouldn't I have been sifting? shouldn't you have been sifting? shouldn't he have been sifting? shouldn't we have been sifting? shouldn't you have been sifting? shouldn't they have been sifting?