English verb conjugation
COULD STRAIGHTEN

Regular verb: straighten - straightened - straightened

Affirmation

Simple form	V-ing form
I could straighten you could straighten she could straighten we could straighten you could straighten they could straighten	I could be straightening you could be straightening she could be straightening we could be straightening you could be straightening they could be straightening
Perfect	V-ing perfect
I could have straightened you could have straightened she could have straightened we could have straightened you could have straightened they could have straightened	I could have been straightening you could have been straightening she could have been straightening we could have been straightening you could have been straightening they could have been straightening

Negation

Simple form	V-ing form
I could not straighten you could not straighten she could not straighten we could not straighten you could not straighten they could not straighten	I could not be straightening you could not be straightening she could not be straightening we could not be straightening you could not be straightening they could not be straightening
Perfect	V-ing perfect
I could not have straightened you could not have straightened she could not have straightened we could not have straightened you could not have straightened they could not have straightened	I could not have been straightening you could not have been straightening she could not have been straightening we could not have been straightening you could not have been straightening they could not have been straightening

Interrogative form

Simple form	V-ing form
could I straighten? could you straighten? could she straighten? could we straighten? could you straighten? could they straighten?	could I be straightening? could you be straightening? could she be straightening? could we be straightening? could you be straightening? could they be straightening?
Perfect	V-ing perfect
could I have straightened? could you have straightened? could she have straightened? could we have straightened? could you have straightened? could they have straightened?	could I have been straightening? could you have been straightening? could she have been straightening? could we have been straightening? could you have been straightening? could they have been straightening?

Interro-negative form

Simple form	V-ing form
could I not straighten? could you not straighten? could she not straighten? could we not straighten? could you not straighten? could they not straighten?	could I not be straightening? could you not be straightening? could she not be straightening? could we not be straightening? could you not be straightening? could they not be straightening?
Perfect	V-ing perfect
could I not have straightened? could you not have straightened? could she not have straightened? could we not have straightened? could you not have straightened? could they not have straightened?	could I not have been straightening? could you not have been straightening? could she not have been straightening? could we not have been straightening? could you not have been straightening? could they not have been straightening?