I could untwist you could untwist he could untwist we could untwist you could untwist they could untwist
V-ing form
I could be untwisting you could be untwisting he could be untwisting we could be untwisting you could be untwisting they could be untwisting
Perfect
I could have untwisted you could have untwisted he could have untwisted we could have untwisted you could have untwisted they could have untwisted
V-ing perfect
I could have been untwisting you could have been untwisting he could have been untwisting we could have been untwisting you could have been untwisting they could have been untwisting
Negation
Simple form
I could not untwist you could not untwist he could not untwist we could not untwist you could not untwist they could not untwist
V-ing form
I could not be untwisting you could not be untwisting he could not be untwisting we could not be untwisting you could not be untwisting they could not be untwisting
Perfect
I could not have untwisted you could not have untwisted he could not have untwisted we could not have untwisted you could not have untwisted they could not have untwisted
V-ing perfect
I could not have been untwisting you could not have been untwisting he could not have been untwisting we could not have been untwisting you could not have been untwisting they could not have been untwisting
Interrogative form
Simple form
could I untwist? could you untwist? could he untwist? could we untwist? could you untwist? could they untwist?
V-ing form
could I be untwisting? could you be untwisting? could he be untwisting? could we be untwisting? could you be untwisting? could they be untwisting?
Perfect
could I have untwisted? could you have untwisted? could he have untwisted? could we have untwisted? could you have untwisted? could they have untwisted?
V-ing perfect
could I have been untwisting? could you have been untwisting? could he have been untwisting? could we have been untwisting? could you have been untwisting? could they have been untwisting?
Interro-negative form
Simple form
could I not untwist? could you not untwist? could he not untwist? could we not untwist? could you not untwist? could they not untwist?
V-ing form
could I not be untwisting? could you not be untwisting? could he not be untwisting? could we not be untwisting? could you not be untwisting? could they not be untwisting?
Perfect
could I not have untwisted? could you not have untwisted? could he not have untwisted? could we not have untwisted? could you not have untwisted? could they not have untwisted?
V-ing perfect
could I not have been untwisting? could you not have been untwisting? could he not have been untwisting? could we not have been untwisting? could you not have been untwisting? could they not have been untwisting?