English verb conjugation
MUST FLATTEN

Regular verb: flatten - flattened - flattened

Affirmation

Simple form	V-ing form
I must flatten you must flatten she must flatten we must flatten you must flatten they must flatten	I must be flattening you must be flattening she must be flattening we must be flattening you must be flattening they must be flattening
Perfect	V-ing perfect
I must have flattened you must have flattened she must have flattened we must have flattened you must have flattened they must have flattened	I must have been flattening you must have been flattening she must have been flattening we must have been flattening you must have been flattening they must have been flattening

Negation

Simple form	V-ing form
I mustn't flatten you mustn't flatten she mustn't flatten we mustn't flatten you mustn't flatten they mustn't flatten	I mustn't be flattening you mustn't be flattening she mustn't be flattening we mustn't be flattening you mustn't be flattening they mustn't be flattening
Perfect	V-ing perfect
I mustn't have flattened you mustn't have flattened she mustn't have flattened we mustn't have flattened you mustn't have flattened they mustn't have flattened	I mustn't have been flattening you mustn't have been flattening she mustn't have been flattening we mustn't have been flattening you mustn't have been flattening they mustn't have been flattening

Interrogative form

Simple form	V-ing form
must I flatten? must you flatten? must she flatten? must we flatten? must you flatten? must they flatten?	must I be flattening? must you be flattening? must she be flattening? must we be flattening? must you be flattening? must they be flattening?
Perfect	V-ing perfect
must I have flattened? must you have flattened? must she have flattened? must we have flattened? must you have flattened? must they have flattened?	must I have been flattening? must you have been flattening? must she have been flattening? must we have been flattening? must you have been flattening? must they have been flattening?

Interro-negative form

Simple form	V-ing form
mustn't I flatten? mustn't you flatten? mustn't she flatten? mustn't we flatten? mustn't you flatten? mustn't they flatten?	mustn't I be flattening? mustn't you be flattening? mustn't she be flattening? mustn't we be flattening? mustn't you be flattening? mustn't they be flattening?
Perfect	V-ing perfect
mustn't I have flattened? mustn't you have flattened? mustn't she have flattened? mustn't we have flattened? mustn't you have flattened? mustn't they have flattened?	mustn't I have been flattening? mustn't you have been flattening? mustn't she have been flattening? mustn't we have been flattening? mustn't you have been flattening? mustn't they have been flattening?