English verb conjugation
COULD UNTHREAD

Regular verb: unthread - unthreaded - unthreaded

Affirmation

Simple form	V-ing form
I could unthread you could unthread she could unthread we could unthread you could unthread they could unthread	I could be unthreading you could be unthreading she could be unthreading we could be unthreading you could be unthreading they could be unthreading
Perfect	V-ing perfect
I could have unthreaded you could have unthreaded she could have unthreaded we could have unthreaded you could have unthreaded they could have unthreaded	I could have been unthreading you could have been unthreading she could have been unthreading we could have been unthreading you could have been unthreading they could have been unthreading

Negation

Simple form	V-ing form
I could not unthread you could not unthread she could not unthread we could not unthread you could not unthread they could not unthread	I could not be unthreading you could not be unthreading she could not be unthreading we could not be unthreading you could not be unthreading they could not be unthreading
Perfect	V-ing perfect
I could not have unthreaded you could not have unthreaded she could not have unthreaded we could not have unthreaded you could not have unthreaded they could not have unthreaded	I could not have been unthreading you could not have been unthreading she could not have been unthreading we could not have been unthreading you could not have been unthreading they could not have been unthreading

Interrogative form

Simple form	V-ing form
could I unthread? could you unthread? could she unthread? could we unthread? could you unthread? could they unthread?	could I be unthreading? could you be unthreading? could she be unthreading? could we be unthreading? could you be unthreading? could they be unthreading?
Perfect	V-ing perfect
could I have unthreaded? could you have unthreaded? could she have unthreaded? could we have unthreaded? could you have unthreaded? could they have unthreaded?	could I have been unthreading? could you have been unthreading? could she have been unthreading? could we have been unthreading? could you have been unthreading? could they have been unthreading?

Interro-negative form

Simple form	V-ing form
could I not unthread? could you not unthread? could she not unthread? could we not unthread? could you not unthread? could they not unthread?	could I not be unthreading? could you not be unthreading? could she not be unthreading? could we not be unthreading? could you not be unthreading? could they not be unthreading?
Perfect	V-ing perfect
could I not have unthreaded? could you not have unthreaded? could she not have unthreaded? could we not have unthreaded? could you not have unthreaded? could they not have unthreaded?	could I not have been unthreading? could you not have been unthreading? could she not have been unthreading? could we not have been unthreading? could you not have been unthreading? could they not have been unthreading?