English verb conjugation
COULD YO-YO

Regular verb: yo-yo - yo-yoed - yo-yoed

Affirmation

Simple form	V-ing form
I could yo-yo you could yo-yo he could yo-yo we could yo-yo you could yo-yo they could yo-yo	I could be yo-yoing you could be yo-yoing he could be yo-yoing we could be yo-yoing you could be yo-yoing they could be yo-yoing
Perfect	V-ing perfect
I could have yo-yoed you could have yo-yoed he could have yo-yoed we could have yo-yoed you could have yo-yoed they could have yo-yoed	I could have been yo-yoing you could have been yo-yoing he could have been yo-yoing we could have been yo-yoing you could have been yo-yoing they could have been yo-yoing

Negation

Simple form	V-ing form
I couldn't yo-yo you couldn't yo-yo he couldn't yo-yo we couldn't yo-yo you couldn't yo-yo they couldn't yo-yo	I couldn't be yo-yoing you couldn't be yo-yoing he couldn't be yo-yoing we couldn't be yo-yoing you couldn't be yo-yoing they couldn't be yo-yoing
Perfect	V-ing perfect
I couldn't have yo-yoed you couldn't have yo-yoed he couldn't have yo-yoed we couldn't have yo-yoed you couldn't have yo-yoed they couldn't have yo-yoed	I couldn't have been yo-yoing you couldn't have been yo-yoing he couldn't have been yo-yoing we couldn't have been yo-yoing you couldn't have been yo-yoing they couldn't have been yo-yoing

Interrogative form

Simple form	V-ing form
could I yo-yo? could you yo-yo? could he yo-yo? could we yo-yo? could you yo-yo? could they yo-yo?	could I be yo-yoing? could you be yo-yoing? could he be yo-yoing? could we be yo-yoing? could you be yo-yoing? could they be yo-yoing?
Perfect	V-ing perfect
could I have yo-yoed? could you have yo-yoed? could he have yo-yoed? could we have yo-yoed? could you have yo-yoed? could they have yo-yoed?	could I have been yo-yoing? could you have been yo-yoing? could he have been yo-yoing? could we have been yo-yoing? could you have been yo-yoing? could they have been yo-yoing?

Interro-negative form

Simple form	V-ing form
couldn't I yo-yo? couldn't you yo-yo? couldn't he yo-yo? couldn't we yo-yo? couldn't you yo-yo? couldn't they yo-yo?	couldn't I be yo-yoing? couldn't you be yo-yoing? couldn't he be yo-yoing? couldn't we be yo-yoing? couldn't you be yo-yoing? couldn't they be yo-yoing?
Perfect	V-ing perfect
couldn't I have yo-yoed? couldn't you have yo-yoed? couldn't he have yo-yoed? couldn't we have yo-yoed? couldn't you have yo-yoed? couldn't they have yo-yoed?	couldn't I have been yo-yoing? couldn't you have been yo-yoing? couldn't he have been yo-yoing? couldn't we have been yo-yoing? couldn't you have been yo-yoing? couldn't they have been yo-yoing?