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