I could sew you could sew she could sew we could sew you could sew they could sew
V-ing form
I could be sewing you could be sewing she could be sewing we could be sewing you could be sewing they could be sewing
Perfect
I could have sewn you could have sewn she could have sewn we could have sewn you could have sewn they could have sewn
V-ing perfect
I could have been sewing you could have been sewing she could have been sewing we could have been sewing you could have been sewing they could have been sewing
Negation
Simple form
I couldn't sew you couldn't sew she couldn't sew we couldn't sew you couldn't sew they couldn't sew
V-ing form
I couldn't be sewing you couldn't be sewing she couldn't be sewing we couldn't be sewing you couldn't be sewing they couldn't be sewing
Perfect
I couldn't have sewn you couldn't have sewn she couldn't have sewn we couldn't have sewn you couldn't have sewn they couldn't have sewn
V-ing perfect
I couldn't have been sewing you couldn't have been sewing she couldn't have been sewing we couldn't have been sewing you couldn't have been sewing they couldn't have been sewing
Interrogative form
Simple form
could I sew? could you sew? could she sew? could we sew? could you sew? could they sew?
V-ing form
could I be sewing? could you be sewing? could she be sewing? could we be sewing? could you be sewing? could they be sewing?
Perfect
could I have sewn? could you have sewn? could she have sewn? could we have sewn? could you have sewn? could they have sewn?
V-ing perfect
could I have been sewing? could you have been sewing? could she have been sewing? could we have been sewing? could you have been sewing? could they have been sewing?
Interro-negative form
Simple form
couldn't I sew? couldn't you sew? couldn't she sew? couldn't we sew? couldn't you sew? couldn't they sew?
V-ing form
couldn't I be sewing? couldn't you be sewing? couldn't she be sewing? couldn't we be sewing? couldn't you be sewing? couldn't they be sewing?
Perfect
couldn't I have sewn? couldn't you have sewn? couldn't she have sewn? couldn't we have sewn? couldn't you have sewn? couldn't they have sewn?
V-ing perfect
couldn't I have been sewing? couldn't you have been sewing? couldn't she have been sewing? couldn't we have been sewing? couldn't you have been sewing? couldn't they have been sewing?