English verb conjugation
MUST STRAIGHTEN

Regular verb: straighten - straightened - straightened

Affirmation

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

Negation

Simple form	V-ing form
I mustn't straighten you mustn't straighten she mustn't straighten we mustn't straighten you mustn't straighten they mustn't straighten	I mustn't be straightening you mustn't be straightening she mustn't be straightening we mustn't be straightening you mustn't be straightening they mustn't be straightening
Perfect	V-ing perfect
I mustn't have straightened you mustn't have straightened she mustn't have straightened we mustn't have straightened you mustn't have straightened they mustn't have straightened	I mustn't have been straightening you mustn't have been straightening she mustn't have been straightening we mustn't have been straightening you mustn't have been straightening they mustn't have been straightening

Interrogative form

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

Interro-negative form

Simple form	V-ing form
mustn't I straighten? mustn't you straighten? mustn't she straighten? mustn't we straighten? mustn't you straighten? mustn't they straighten?	mustn't I be straightening? mustn't you be straightening? mustn't she be straightening? mustn't we be straightening? mustn't you be straightening? mustn't they be straightening?
Perfect	V-ing perfect
mustn't I have straightened? mustn't you have straightened? mustn't she have straightened? mustn't we have straightened? mustn't you have straightened? mustn't they have straightened?	mustn't I have been straightening? mustn't you have been straightening? mustn't she have been straightening? mustn't we have been straightening? mustn't you have been straightening? mustn't they have been straightening?