English verb conjugation
COULD STY

Regular verb: sty - stied - stied

Affirmation

Simple form	V-ing form
I could sty you could sty he could sty we could sty you could sty they could sty	I could be stying you could be stying he could be stying we could be stying you could be stying they could be stying
Perfect	V-ing perfect
I could have stied you could have stied he could have stied we could have stied you could have stied they could have stied	I could have been stying you could have been stying he could have been stying we could have been stying you could have been stying they could have been stying

Negation

Simple form	V-ing form
I couldn't sty you couldn't sty he couldn't sty we couldn't sty you couldn't sty they couldn't sty	I couldn't be stying you couldn't be stying he couldn't be stying we couldn't be stying you couldn't be stying they couldn't be stying
Perfect	V-ing perfect
I couldn't have stied you couldn't have stied he couldn't have stied we couldn't have stied you couldn't have stied they couldn't have stied	I couldn't have been stying you couldn't have been stying he couldn't have been stying we couldn't have been stying you couldn't have been stying they couldn't have been stying

Interrogative form

Simple form	V-ing form
could I sty? could you sty? could he sty? could we sty? could you sty? could they sty?	could I be stying? could you be stying? could he be stying? could we be stying? could you be stying? could they be stying?
Perfect	V-ing perfect
could I have stied? could you have stied? could he have stied? could we have stied? could you have stied? could they have stied?	could I have been stying? could you have been stying? could he have been stying? could we have been stying? could you have been stying? could they have been stying?

Interro-negative form

Simple form	V-ing form
couldn't I sty? couldn't you sty? couldn't he sty? couldn't we sty? couldn't you sty? couldn't they sty?	couldn't I be stying? couldn't you be stying? couldn't he be stying? couldn't we be stying? couldn't you be stying? couldn't they be stying?
Perfect	V-ing perfect
couldn't I have stied? couldn't you have stied? couldn't he have stied? couldn't we have stied? couldn't you have stied? couldn't they have stied?	couldn't I have been stying? couldn't you have been stying? couldn't he have been stying? couldn't we have been stying? couldn't you have been stying? couldn't they have been stying?