I could fit you could fit he could fit we could fit you could fit they could fit
V-ing form
I could be fitting you could be fitting he could be fitting we could be fitting you could be fitting they could be fitting
Perfect
I could have fit, fitted you could have fit, fitted he could have fit, fitted we could have fit, fitted you could have fit, fitted they could have fit, fitted
V-ing perfect
I could have been fitting you could have been fitting he could have been fitting we could have been fitting you could have been fitting they could have been fitting
Negation
Simple form
I couldn't fit you couldn't fit he couldn't fit we couldn't fit you couldn't fit they couldn't fit
V-ing form
I couldn't be fitting you couldn't be fitting he couldn't be fitting we couldn't be fitting you couldn't be fitting they couldn't be fitting
Perfect
I couldn't have fit, fitted you couldn't have fit, fitted he couldn't have fit, fitted we couldn't have fit, fitted you couldn't have fit, fitted they couldn't have fit, fitted
V-ing perfect
I couldn't have been fitting you couldn't have been fitting he couldn't have been fitting we couldn't have been fitting you couldn't have been fitting they couldn't have been fitting
Interrogative form
Simple form
could I fit? could you fit? could he fit? could we fit? could you fit? could they fit?
V-ing form
could I be fitting? could you be fitting? could he be fitting? could we be fitting? could you be fitting? could they be fitting?
Perfect
could I have fit, fitted? could you have fit, fitted? could he have fit, fitted? could we have fit, fitted? could you have fit, fitted? could they have fit, fitted?
V-ing perfect
could I have been fitting? could you have been fitting? could he have been fitting? could we have been fitting? could you have been fitting? could they have been fitting?
Interro-negative form
Simple form
couldn't I fit? couldn't you fit? couldn't he fit? couldn't we fit? couldn't you fit? couldn't they fit?
V-ing form
couldn't I be fitting? couldn't you be fitting? couldn't he be fitting? couldn't we be fitting? couldn't you be fitting? couldn't they be fitting?
Perfect
couldn't I have fit, fitted? couldn't you have fit, fitted? couldn't he have fit, fitted? couldn't we have fit, fitted? couldn't you have fit, fitted? couldn't they have fit, fitted?
V-ing perfect
couldn't I have been fitting? couldn't you have been fitting? couldn't he have been fitting? couldn't we have been fitting? couldn't you have been fitting? couldn't they have been fitting?