English verb conjugation
COULD YES

Regular verb: yes - yesed - yesed

Affirmation

Simple form	V-ing form
I could yes you could yes he could yes we could yes you could yes they could yes	I could be yesing you could be yesing he could be yesing we could be yesing you could be yesing they could be yesing
Perfect	V-ing perfect
I could have yesed you could have yesed he could have yesed we could have yesed you could have yesed they could have yesed	I could have been yesing you could have been yesing he could have been yesing we could have been yesing you could have been yesing they could have been yesing

Negation

Simple form	V-ing form
I could not yes you could not yes he could not yes we could not yes you could not yes they could not yes	I could not be yesing you could not be yesing he could not be yesing we could not be yesing you could not be yesing they could not be yesing
Perfect	V-ing perfect
I could not have yesed you could not have yesed he could not have yesed we could not have yesed you could not have yesed they could not have yesed	I could not have been yesing you could not have been yesing he could not have been yesing we could not have been yesing you could not have been yesing they could not have been yesing

Interrogative form

Simple form	V-ing form
could I yes? could you yes? could he yes? could we yes? could you yes? could they yes?	could I be yesing? could you be yesing? could he be yesing? could we be yesing? could you be yesing? could they be yesing?
Perfect	V-ing perfect
could I have yesed? could you have yesed? could he have yesed? could we have yesed? could you have yesed? could they have yesed?	could I have been yesing? could you have been yesing? could he have been yesing? could we have been yesing? could you have been yesing? could they have been yesing?

Interro-negative form

Simple form	V-ing form
could I not yes? could you not yes? could he not yes? could we not yes? could you not yes? could they not yes?	could I not be yesing? could you not be yesing? could he not be yesing? could we not be yesing? could you not be yesing? could they not be yesing?
Perfect	V-ing perfect
could I not have yesed? could you not have yesed? could he not have yesed? could we not have yesed? could you not have yesed? could they not have yesed?	could I not have been yesing? could you not have been yesing? could he not have been yesing? could we not have been yesing? could you not have been yesing? could they not have been yesing?