English verb conjugation
MUST THUMB

Regular verb: thumb - thumbed - thumbed

Affirmation

Simple form	V-ing form
I must thumb you must thumb he must thumb we must thumb you must thumb they must thumb	I must be thumbing you must be thumbing he must be thumbing we must be thumbing you must be thumbing they must be thumbing
Perfect	V-ing perfect
I must have thumbed you must have thumbed he must have thumbed we must have thumbed you must have thumbed they must have thumbed	I must have been thumbing you must have been thumbing he must have been thumbing we must have been thumbing you must have been thumbing they must have been thumbing

Negation

Simple form	V-ing form
I mustn't thumb you mustn't thumb he mustn't thumb we mustn't thumb you mustn't thumb they mustn't thumb	I mustn't be thumbing you mustn't be thumbing he mustn't be thumbing we mustn't be thumbing you mustn't be thumbing they mustn't be thumbing
Perfect	V-ing perfect
I mustn't have thumbed you mustn't have thumbed he mustn't have thumbed we mustn't have thumbed you mustn't have thumbed they mustn't have thumbed	I mustn't have been thumbing you mustn't have been thumbing he mustn't have been thumbing we mustn't have been thumbing you mustn't have been thumbing they mustn't have been thumbing

Interrogative form

Simple form	V-ing form
must I thumb? must you thumb? must he thumb? must we thumb? must you thumb? must they thumb?	must I be thumbing? must you be thumbing? must he be thumbing? must we be thumbing? must you be thumbing? must they be thumbing?
Perfect	V-ing perfect
must I have thumbed? must you have thumbed? must he have thumbed? must we have thumbed? must you have thumbed? must they have thumbed?	must I have been thumbing? must you have been thumbing? must he have been thumbing? must we have been thumbing? must you have been thumbing? must they have been thumbing?

Interro-negative form

Simple form	V-ing form
mustn't I thumb? mustn't you thumb? mustn't he thumb? mustn't we thumb? mustn't you thumb? mustn't they thumb?	mustn't I be thumbing? mustn't you be thumbing? mustn't he be thumbing? mustn't we be thumbing? mustn't you be thumbing? mustn't they be thumbing?
Perfect	V-ing perfect
mustn't I have thumbed? mustn't you have thumbed? mustn't he have thumbed? mustn't we have thumbed? mustn't you have thumbed? mustn't they have thumbed?	mustn't I have been thumbing? mustn't you have been thumbing? mustn't he have been thumbing? mustn't we have been thumbing? mustn't you have been thumbing? mustn't they have been thumbing?