I could shred you could shred he could shred we could shred you could shred they could shred
V-ing form
I could be shredding you could be shredding he could be shredding we could be shredding you could be shredding they could be shredding
Perfect
I could have shredded you could have shredded he could have shredded we could have shredded you could have shredded they could have shredded
V-ing perfect
I could have been shredding you could have been shredding he could have been shredding we could have been shredding you could have been shredding they could have been shredding
Negation
Simple form
I couldn't shred you couldn't shred he couldn't shred we couldn't shred you couldn't shred they couldn't shred
V-ing form
I couldn't be shredding you couldn't be shredding he couldn't be shredding we couldn't be shredding you couldn't be shredding they couldn't be shredding
Perfect
I couldn't have shredded you couldn't have shredded he couldn't have shredded we couldn't have shredded you couldn't have shredded they couldn't have shredded
V-ing perfect
I couldn't have been shredding you couldn't have been shredding he couldn't have been shredding we couldn't have been shredding you couldn't have been shredding they couldn't have been shredding
Interrogative form
Simple form
could I shred? could you shred? could he shred? could we shred? could you shred? could they shred?
V-ing form
could I be shredding? could you be shredding? could he be shredding? could we be shredding? could you be shredding? could they be shredding?
Perfect
could I have shredded? could you have shredded? could he have shredded? could we have shredded? could you have shredded? could they have shredded?
V-ing perfect
could I have been shredding? could you have been shredding? could he have been shredding? could we have been shredding? could you have been shredding? could they have been shredding?
Interro-negative form
Simple form
couldn't I shred? couldn't you shred? couldn't he shred? couldn't we shred? couldn't you shred? couldn't they shred?
V-ing form
couldn't I be shredding? couldn't you be shredding? couldn't he be shredding? couldn't we be shredding? couldn't you be shredding? couldn't they be shredding?
Perfect
couldn't I have shredded? couldn't you have shredded? couldn't he have shredded? couldn't we have shredded? couldn't you have shredded? couldn't they have shredded?
V-ing perfect
couldn't I have been shredding? couldn't you have been shredding? couldn't he have been shredding? couldn't we have been shredding? couldn't you have been shredding? couldn't they have been shredding?