I could describe you could describe he could describe we could describe you could describe they could describe
V-ing form
I could be describing you could be describing he could be describing we could be describing you could be describing they could be describing
Perfect
I could have described you could have described he could have described we could have described you could have described they could have described
V-ing perfect
I could have been describing you could have been describing he could have been describing we could have been describing you could have been describing they could have been describing
Negation
Simple form
I could not describe you could not describe he could not describe we could not describe you could not describe they could not describe
V-ing form
I could not be describing you could not be describing he could not be describing we could not be describing you could not be describing they could not be describing
Perfect
I could not have described you could not have described he could not have described we could not have described you could not have described they could not have described
V-ing perfect
I could not have been describing you could not have been describing he could not have been describing we could not have been describing you could not have been describing they could not have been describing
Interrogative form
Simple form
could I describe? could you describe? could he describe? could we describe? could you describe? could they describe?
V-ing form
could I be describing? could you be describing? could he be describing? could we be describing? could you be describing? could they be describing?
Perfect
could I have described? could you have described? could he have described? could we have described? could you have described? could they have described?
V-ing perfect
could I have been describing? could you have been describing? could he have been describing? could we have been describing? could you have been describing? could they have been describing?
Interro-negative form
Simple form
could I not describe? could you not describe? could he not describe? could we not describe? could you not describe? could they not describe?
V-ing form
could I not be describing? could you not be describing? could he not be describing? could we not be describing? could you not be describing? could they not be describing?
Perfect
could I not have described? could you not have described? could he not have described? could we not have described? could you not have described? could they not have described?
V-ing perfect
could I not have been describing? could you not have been describing? could he not have been describing? could we not have been describing? could you not have been describing? could they not have been describing?