English verb conjugation
COULD PIPE

Regular verb: pipe - piped - piped

Affirmation

Simple form	V-ing form
I could pipe you could pipe he could pipe we could pipe you could pipe they could pipe	I could be piping you could be piping he could be piping we could be piping you could be piping they could be piping
Perfect	V-ing perfect
I could have piped you could have piped he could have piped we could have piped you could have piped they could have piped	I could have been piping you could have been piping he could have been piping we could have been piping you could have been piping they could have been piping

Negation

Simple form	V-ing form
I could not pipe you could not pipe he could not pipe we could not pipe you could not pipe they could not pipe	I could not be piping you could not be piping he could not be piping we could not be piping you could not be piping they could not be piping
Perfect	V-ing perfect
I could not have piped you could not have piped he could not have piped we could not have piped you could not have piped they could not have piped	I could not have been piping you could not have been piping he could not have been piping we could not have been piping you could not have been piping they could not have been piping

Interrogative form

Simple form	V-ing form
could I pipe? could you pipe? could he pipe? could we pipe? could you pipe? could they pipe?	could I be piping? could you be piping? could he be piping? could we be piping? could you be piping? could they be piping?
Perfect	V-ing perfect
could I have piped? could you have piped? could he have piped? could we have piped? could you have piped? could they have piped?	could I have been piping? could you have been piping? could he have been piping? could we have been piping? could you have been piping? could they have been piping?

Interro-negative form

Simple form	V-ing form
could I not pipe? could you not pipe? could he not pipe? could we not pipe? could you not pipe? could they not pipe?	could I not be piping? could you not be piping? could he not be piping? could we not be piping? could you not be piping? could they not be piping?
Perfect	V-ing perfect
could I not have piped? could you not have piped? could he not have piped? could we not have piped? could you not have piped? could they not have piped?	could I not have been piping? could you not have been piping? could he not have been piping? could we not have been piping? could you not have been piping? could they not have been piping?