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