I could shut you could shut he could shut we could shut you could shut they could shut
V-ing form
I could be shutting you could be shutting he could be shutting we could be shutting you could be shutting they could be shutting
Perfect
I could have shut you could have shut he could have shut we could have shut you could have shut they could have shut
V-ing perfect
I could have been shutting you could have been shutting he could have been shutting we could have been shutting you could have been shutting they could have been shutting
Negation
Simple form
I could not shut you could not shut he could not shut we could not shut you could not shut they could not shut
V-ing form
I could not be shutting you could not be shutting he could not be shutting we could not be shutting you could not be shutting they could not be shutting
Perfect
I could not have shut you could not have shut he could not have shut we could not have shut you could not have shut they could not have shut
V-ing perfect
I could not have been shutting you could not have been shutting he could not have been shutting we could not have been shutting you could not have been shutting they could not have been shutting
Interrogative form
Simple form
could I shut? could you shut? could he shut? could we shut? could you shut? could they shut?
V-ing form
could I be shutting? could you be shutting? could he be shutting? could we be shutting? could you be shutting? could they be shutting?
Perfect
could I have shut? could you have shut? could he have shut? could we have shut? could you have shut? could they have shut?
V-ing perfect
could I have been shutting? could you have been shutting? could he have been shutting? could we have been shutting? could you have been shutting? could they have been shutting?
Interro-negative form
Simple form
could I not shut? could you not shut? could he not shut? could we not shut? could you not shut? could they not shut?
V-ing form
could I not be shutting? could you not be shutting? could he not be shutting? could we not be shutting? could you not be shutting? could they not be shutting?
Perfect
could I not have shut? could you not have shut? could he not have shut? could we not have shut? could you not have shut? could they not have shut?
V-ing perfect
could I not have been shutting? could you not have been shutting? could he not have been shutting? could we not have been shutting? could you not have been shutting? could they not have been shutting?