English verb conjugation
COULD STY

Regular verb: sty - stied - stied

Affirmation

Simple form	V-ing form
I could sty you could sty she could sty we could sty you could sty they could sty	I could be stying you could be stying she 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 she 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 she 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 she 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 she 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 she 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 she 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 she sty? could we sty? could you sty? could they sty?	could I be stying? could you be stying? could she 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 she 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 she 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 she 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 she 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 she 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 she have been stying? couldn't we have been stying? couldn't you have been stying? couldn't they have been stying?