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