I can sift you can sift she can sift we can sift you can sift they can sift
V-ing form
I can be sifting you can be sifting she can be sifting we can be sifting you can be sifting they can be sifting
Perfect
I can have sifted you can have sifted she can have sifted we can have sifted you can have sifted they can have sifted
V-ing perfect
I can have been sifting you can have been sifting she can have been sifting we can have been sifting you can have been sifting they can have been sifting
Negation
Simple form
I can't sift you can't sift she can't sift we can't sift you can't sift they can't sift
V-ing form
I can't be sifting you can't be sifting she can't be sifting we can't be sifting you can't be sifting they can't be sifting
Perfect
I can't have sifted you can't have sifted she can't have sifted we can't have sifted you can't have sifted they can't have sifted
V-ing perfect
I can't have been sifting you can't have been sifting she can't have been sifting we can't have been sifting you can't have been sifting they can't have been sifting
Interrogative form
Simple form
can I sift? can you sift? can she sift? can we sift? can you sift? can they sift?
V-ing form
can I be sifting? can you be sifting? can she be sifting? can we be sifting? can you be sifting? can they be sifting?
Perfect
can I have sifted? can you have sifted? can she have sifted? can we have sifted? can you have sifted? can they have sifted?
V-ing perfect
can I have been sifting? can you have been sifting? can she have been sifting? can we have been sifting? can you have been sifting? can they have been sifting?
Interro-negative form
Simple form
can't I sift? can't you sift? can't she sift? can't we sift? can't you sift? can't they sift?
V-ing form
can't I be sifting? can't you be sifting? can't she be sifting? can't we be sifting? can't you be sifting? can't they be sifting?
Perfect
can't I have sifted? can't you have sifted? can't she have sifted? can't we have sifted? can't you have sifted? can't they have sifted?
V-ing perfect
can't I have been sifting? can't you have been sifting? can't she have been sifting? can't we have been sifting? can't you have been sifting? can't they have been sifting?