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