English verb conjugation
MUST GRIN

Regular verb: grin - grinned - grinned

Affirmation

Simple form	V-ing form
I must grin you must grin he must grin we must grin you must grin they must grin	I must be grinning you must be grinning he must be grinning we must be grinning you must be grinning they must be grinning
Perfect	V-ing perfect
I must have grinned you must have grinned he must have grinned we must have grinned you must have grinned they must have grinned	I must have been grinning you must have been grinning he must have been grinning we must have been grinning you must have been grinning they must have been grinning

Negation

Simple form	V-ing form
I must not grin you must not grin he must not grin we must not grin you must not grin they must not grin	I must not be grinning you must not be grinning he must not be grinning we must not be grinning you must not be grinning they must not be grinning
Perfect	V-ing perfect
I must not have grinned you must not have grinned he must not have grinned we must not have grinned you must not have grinned they must not have grinned	I must not have been grinning you must not have been grinning he must not have been grinning we must not have been grinning you must not have been grinning they must not have been grinning

Interrogative form

Simple form	V-ing form
must I grin? must you grin? must he grin? must we grin? must you grin? must they grin?	must I be grinning? must you be grinning? must he be grinning? must we be grinning? must you be grinning? must they be grinning?
Perfect	V-ing perfect
must I have grinned? must you have grinned? must he have grinned? must we have grinned? must you have grinned? must they have grinned?	must I have been grinning? must you have been grinning? must he have been grinning? must we have been grinning? must you have been grinning? must they have been grinning?

Interro-negative form

Simple form	V-ing form
must I not grin? must you not grin? must he not grin? must we not grin? must you not grin? must they not grin?	must I not be grinning? must you not be grinning? must he not be grinning? must we not be grinning? must you not be grinning? must they not be grinning?
Perfect	V-ing perfect
must I not have grinned? must you not have grinned? must he not have grinned? must we not have grinned? must you not have grinned? must they not have grinned?	must I not have been grinning? must you not have been grinning? must he not have been grinning? must we not have been grinning? must you not have been grinning? must they not have been grinning?