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 couldn't untwist you couldn't untwist he couldn't untwist we couldn't untwist you couldn't untwist they couldn't untwist
V-ing form
I couldn't be untwisting you couldn't be untwisting he couldn't be untwisting we couldn't be untwisting you couldn't be untwisting they couldn't be untwisting
Perfect
I couldn't have untwisted you couldn't have untwisted he couldn't have untwisted we couldn't have untwisted you couldn't have untwisted they couldn't have untwisted
V-ing perfect
I couldn't have been untwisting you couldn't have been untwisting he couldn't have been untwisting we couldn't have been untwisting you couldn't have been untwisting they couldn't 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
couldn't I untwist? couldn't you untwist? couldn't he untwist? couldn't we untwist? couldn't you untwist? couldn't they untwist?
V-ing form
couldn't I be untwisting? couldn't you be untwisting? couldn't he be untwisting? couldn't we be untwisting? couldn't you be untwisting? couldn't they be untwisting?
Perfect
couldn't I have untwisted? couldn't you have untwisted? couldn't he have untwisted? couldn't we have untwisted? couldn't you have untwisted? couldn't they have untwisted?
V-ing perfect
couldn't I have been untwisting? couldn't you have been untwisting? couldn't he have been untwisting? couldn't we have been untwisting? couldn't you have been untwisting? couldn't they have been untwisting?