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 must not thumb you must not thumb he must not thumb we must not thumb you must not thumb they must not thumb	I must not be thumbing you must not be thumbing he must not be thumbing we must not be thumbing you must not be thumbing they must not be thumbing
Perfect	V-ing perfect
I must not have thumbed you must not have thumbed he must not have thumbed we must not have thumbed you must not have thumbed they must not have thumbed	I must not have been thumbing you must not have been thumbing he must not have been thumbing we must not have been thumbing you must not have been thumbing they must not 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
must I not thumb? must you not thumb? must he not thumb? must we not thumb? must you not thumb? must they not thumb?	must I not be thumbing? must you not be thumbing? must he not be thumbing? must we not be thumbing? must you not be thumbing? must they not be thumbing?
Perfect	V-ing perfect
must I not have thumbed? must you not have thumbed? must he not have thumbed? must we not have thumbed? must you not have thumbed? must they not have thumbed?	must I not have been thumbing? must you not have been thumbing? must he not have been thumbing? must we not have been thumbing? must you not have been thumbing? must they not have been thumbing?