English verb conjugation
MUST FRET

Regular verb: fret - fretted - fretted

Affirmation

Simple form	V-ing form
I must fret you must fret she must fret we must fret you must fret they must fret	I must be fretting you must be fretting she must be fretting we must be fretting you must be fretting they must be fretting
Perfect	V-ing perfect
I must have fretted you must have fretted she must have fretted we must have fretted you must have fretted they must have fretted	I must have been fretting you must have been fretting she must have been fretting we must have been fretting you must have been fretting they must have been fretting

Negation

Simple form	V-ing form
I mustn't fret you mustn't fret she mustn't fret we mustn't fret you mustn't fret they mustn't fret	I mustn't be fretting you mustn't be fretting she mustn't be fretting we mustn't be fretting you mustn't be fretting they mustn't be fretting
Perfect	V-ing perfect
I mustn't have fretted you mustn't have fretted she mustn't have fretted we mustn't have fretted you mustn't have fretted they mustn't have fretted	I mustn't have been fretting you mustn't have been fretting she mustn't have been fretting we mustn't have been fretting you mustn't have been fretting they mustn't have been fretting

Interrogative form

Simple form	V-ing form
must I fret? must you fret? must she fret? must we fret? must you fret? must they fret?	must I be fretting? must you be fretting? must she be fretting? must we be fretting? must you be fretting? must they be fretting?
Perfect	V-ing perfect
must I have fretted? must you have fretted? must she have fretted? must we have fretted? must you have fretted? must they have fretted?	must I have been fretting? must you have been fretting? must she have been fretting? must we have been fretting? must you have been fretting? must they have been fretting?

Interro-negative form

Simple form	V-ing form
mustn't I fret? mustn't you fret? mustn't she fret? mustn't we fret? mustn't you fret? mustn't they fret?	mustn't I be fretting? mustn't you be fretting? mustn't she be fretting? mustn't we be fretting? mustn't you be fretting? mustn't they be fretting?
Perfect	V-ing perfect
mustn't I have fretted? mustn't you have fretted? mustn't she have fretted? mustn't we have fretted? mustn't you have fretted? mustn't they have fretted?	mustn't I have been fretting? mustn't you have been fretting? mustn't she have been fretting? mustn't we have been fretting? mustn't you have been fretting? mustn't they have been fretting?