I could taboo you could taboo he could taboo we could taboo you could taboo they could taboo
V-ing form
I could be tabooing you could be tabooing he could be tabooing we could be tabooing you could be tabooing they could be tabooing
Perfect
I could have tabooed you could have tabooed he could have tabooed we could have tabooed you could have tabooed they could have tabooed
V-ing perfect
I could have been tabooing you could have been tabooing he could have been tabooing we could have been tabooing you could have been tabooing they could have been tabooing
Negation
Simple form
I could not taboo you could not taboo he could not taboo we could not taboo you could not taboo they could not taboo
V-ing form
I could not be tabooing you could not be tabooing he could not be tabooing we could not be tabooing you could not be tabooing they could not be tabooing
Perfect
I could not have tabooed you could not have tabooed he could not have tabooed we could not have tabooed you could not have tabooed they could not have tabooed
V-ing perfect
I could not have been tabooing you could not have been tabooing he could not have been tabooing we could not have been tabooing you could not have been tabooing they could not have been tabooing
Interrogative form
Simple form
could I taboo? could you taboo? could he taboo? could we taboo? could you taboo? could they taboo?
V-ing form
could I be tabooing? could you be tabooing? could he be tabooing? could we be tabooing? could you be tabooing? could they be tabooing?
Perfect
could I have tabooed? could you have tabooed? could he have tabooed? could we have tabooed? could you have tabooed? could they have tabooed?
V-ing perfect
could I have been tabooing? could you have been tabooing? could he have been tabooing? could we have been tabooing? could you have been tabooing? could they have been tabooing?
Interro-negative form
Simple form
could I not taboo? could you not taboo? could he not taboo? could we not taboo? could you not taboo? could they not taboo?
V-ing form
could I not be tabooing? could you not be tabooing? could he not be tabooing? could we not be tabooing? could you not be tabooing? could they not be tabooing?
Perfect
could I not have tabooed? could you not have tabooed? could he not have tabooed? could we not have tabooed? could you not have tabooed? could they not have tabooed?
V-ing perfect
could I not have been tabooing? could you not have been tabooing? could he not have been tabooing? could we not have been tabooing? could you not have been tabooing? could they not have been tabooing?