I could slip-stitch you could slip-stitch he could slip-stitch we could slip-stitch you could slip-stitch they could slip-stitch
V-ing form
I could be slip-stitching you could be slip-stitching he could be slip-stitching we could be slip-stitching you could be slip-stitching they could be slip-stitching
Perfect
I could have slip-stitched you could have slip-stitched he could have slip-stitched we could have slip-stitched you could have slip-stitched they could have slip-stitched
V-ing perfect
I could have been slip-stitching you could have been slip-stitching he could have been slip-stitching we could have been slip-stitching you could have been slip-stitching they could have been slip-stitching
Negation
Simple form
I couldn't slip-stitch you couldn't slip-stitch he couldn't slip-stitch we couldn't slip-stitch you couldn't slip-stitch they couldn't slip-stitch
V-ing form
I couldn't be slip-stitching you couldn't be slip-stitching he couldn't be slip-stitching we couldn't be slip-stitching you couldn't be slip-stitching they couldn't be slip-stitching
Perfect
I couldn't have slip-stitched you couldn't have slip-stitched he couldn't have slip-stitched we couldn't have slip-stitched you couldn't have slip-stitched they couldn't have slip-stitched
V-ing perfect
I couldn't have been slip-stitching you couldn't have been slip-stitching he couldn't have been slip-stitching we couldn't have been slip-stitching you couldn't have been slip-stitching they couldn't have been slip-stitching
Interrogative form
Simple form
could I slip-stitch? could you slip-stitch? could he slip-stitch? could we slip-stitch? could you slip-stitch? could they slip-stitch?
V-ing form
could I be slip-stitching? could you be slip-stitching? could he be slip-stitching? could we be slip-stitching? could you be slip-stitching? could they be slip-stitching?
Perfect
could I have slip-stitched? could you have slip-stitched? could he have slip-stitched? could we have slip-stitched? could you have slip-stitched? could they have slip-stitched?
V-ing perfect
could I have been slip-stitching? could you have been slip-stitching? could he have been slip-stitching? could we have been slip-stitching? could you have been slip-stitching? could they have been slip-stitching?
Interro-negative form
Simple form
couldn't I slip-stitch? couldn't you slip-stitch? couldn't he slip-stitch? couldn't we slip-stitch? couldn't you slip-stitch? couldn't they slip-stitch?
V-ing form
couldn't I be slip-stitching? couldn't you be slip-stitching? couldn't he be slip-stitching? couldn't we be slip-stitching? couldn't you be slip-stitching? couldn't they be slip-stitching?
Perfect
couldn't I have slip-stitched? couldn't you have slip-stitched? couldn't he have slip-stitched? couldn't we have slip-stitched? couldn't you have slip-stitched? couldn't they have slip-stitched?
V-ing perfect
couldn't I have been slip-stitching? couldn't you have been slip-stitching? couldn't he have been slip-stitching? couldn't we have been slip-stitching? couldn't you have been slip-stitching? couldn't they have been slip-stitching?