I could boo-hoo you could boo-hoo he could boo-hoo we could boo-hoo you could boo-hoo they could boo-hoo
V-ing form
I could be boo-hooing you could be boo-hooing he could be boo-hooing we could be boo-hooing you could be boo-hooing they could be boo-hooing
Perfect
I could have boo-hooed you could have boo-hooed he could have boo-hooed we could have boo-hooed you could have boo-hooed they could have boo-hooed
V-ing perfect
I could have been boo-hooing you could have been boo-hooing he could have been boo-hooing we could have been boo-hooing you could have been boo-hooing they could have been boo-hooing
Negation
Simple form
I could not boo-hoo you could not boo-hoo he could not boo-hoo we could not boo-hoo you could not boo-hoo they could not boo-hoo
V-ing form
I could not be boo-hooing you could not be boo-hooing he could not be boo-hooing we could not be boo-hooing you could not be boo-hooing they could not be boo-hooing
Perfect
I could not have boo-hooed you could not have boo-hooed he could not have boo-hooed we could not have boo-hooed you could not have boo-hooed they could not have boo-hooed
V-ing perfect
I could not have been boo-hooing you could not have been boo-hooing he could not have been boo-hooing we could not have been boo-hooing you could not have been boo-hooing they could not have been boo-hooing
Interrogative form
Simple form
could I boo-hoo? could you boo-hoo? could he boo-hoo? could we boo-hoo? could you boo-hoo? could they boo-hoo?
V-ing form
could I be boo-hooing? could you be boo-hooing? could he be boo-hooing? could we be boo-hooing? could you be boo-hooing? could they be boo-hooing?
Perfect
could I have boo-hooed? could you have boo-hooed? could he have boo-hooed? could we have boo-hooed? could you have boo-hooed? could they have boo-hooed?
V-ing perfect
could I have been boo-hooing? could you have been boo-hooing? could he have been boo-hooing? could we have been boo-hooing? could you have been boo-hooing? could they have been boo-hooing?
Interro-negative form
Simple form
could I not boo-hoo? could you not boo-hoo? could he not boo-hoo? could we not boo-hoo? could you not boo-hoo? could they not boo-hoo?
V-ing form
could I not be boo-hooing? could you not be boo-hooing? could he not be boo-hooing? could we not be boo-hooing? could you not be boo-hooing? could they not be boo-hooing?
Perfect
could I not have boo-hooed? could you not have boo-hooed? could he not have boo-hooed? could we not have boo-hooed? could you not have boo-hooed? could they not have boo-hooed?
V-ing perfect
could I not have been boo-hooing? could you not have been boo-hooing? could he not have been boo-hooing? could we not have been boo-hooing? could you not have been boo-hooing? could they not have been boo-hooing?