English verb conjugation
MUST PREEN

Regular verb: preen - preened - preened

Affirmation

Simple form	V-ing form
I must preen you must preen she must preen we must preen you must preen they must preen	I must be preening you must be preening she must be preening we must be preening you must be preening they must be preening
Perfect	V-ing perfect
I must have preened you must have preened she must have preened we must have preened you must have preened they must have preened	I must have been preening you must have been preening she must have been preening we must have been preening you must have been preening they must have been preening

Negation

Simple form	V-ing form
I mustn't preen you mustn't preen she mustn't preen we mustn't preen you mustn't preen they mustn't preen	I mustn't be preening you mustn't be preening she mustn't be preening we mustn't be preening you mustn't be preening they mustn't be preening
Perfect	V-ing perfect
I mustn't have preened you mustn't have preened she mustn't have preened we mustn't have preened you mustn't have preened they mustn't have preened	I mustn't have been preening you mustn't have been preening she mustn't have been preening we mustn't have been preening you mustn't have been preening they mustn't have been preening

Interrogative form

Simple form	V-ing form
must I preen? must you preen? must she preen? must we preen? must you preen? must they preen?	must I be preening? must you be preening? must she be preening? must we be preening? must you be preening? must they be preening?
Perfect	V-ing perfect
must I have preened? must you have preened? must she have preened? must we have preened? must you have preened? must they have preened?	must I have been preening? must you have been preening? must she have been preening? must we have been preening? must you have been preening? must they have been preening?

Interro-negative form

Simple form	V-ing form
mustn't I preen? mustn't you preen? mustn't she preen? mustn't we preen? mustn't you preen? mustn't they preen?	mustn't I be preening? mustn't you be preening? mustn't she be preening? mustn't we be preening? mustn't you be preening? mustn't they be preening?
Perfect	V-ing perfect
mustn't I have preened? mustn't you have preened? mustn't she have preened? mustn't we have preened? mustn't you have preened? mustn't they have preened?	mustn't I have been preening? mustn't you have been preening? mustn't she have been preening? mustn't we have been preening? mustn't you have been preening? mustn't they have been preening?