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 couldn't taboo you couldn't taboo he couldn't taboo we couldn't taboo you couldn't taboo they couldn't taboo
V-ing form
I couldn't be tabooing you couldn't be tabooing he couldn't be tabooing we couldn't be tabooing you couldn't be tabooing they couldn't be tabooing
Perfect
I couldn't have tabooed you couldn't have tabooed he couldn't have tabooed we couldn't have tabooed you couldn't have tabooed they couldn't have tabooed
V-ing perfect
I couldn't have been tabooing you couldn't have been tabooing he couldn't have been tabooing we couldn't have been tabooing you couldn't have been tabooing they couldn't 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
couldn't I taboo? couldn't you taboo? couldn't he taboo? couldn't we taboo? couldn't you taboo? couldn't they taboo?
V-ing form
couldn't I be tabooing? couldn't you be tabooing? couldn't he be tabooing? couldn't we be tabooing? couldn't you be tabooing? couldn't they be tabooing?
Perfect
couldn't I have tabooed? couldn't you have tabooed? couldn't he have tabooed? couldn't we have tabooed? couldn't you have tabooed? couldn't they have tabooed?
V-ing perfect
couldn't I have been tabooing? couldn't you have been tabooing? couldn't he have been tabooing? couldn't we have been tabooing? couldn't you have been tabooing? couldn't they have been tabooing?