English verb conjugation
MUST CROAK

Regular verb: croak - croaked - croaked

Affirmation

Simple form	V-ing form
I must croak you must croak he must croak we must croak you must croak they must croak	I must be croaking you must be croaking he must be croaking we must be croaking you must be croaking they must be croaking
Perfect	V-ing perfect
I must have croaked you must have croaked he must have croaked we must have croaked you must have croaked they must have croaked	I must have been croaking you must have been croaking he must have been croaking we must have been croaking you must have been croaking they must have been croaking

Negation

Simple form	V-ing form
I must not croak you must not croak he must not croak we must not croak you must not croak they must not croak	I must not be croaking you must not be croaking he must not be croaking we must not be croaking you must not be croaking they must not be croaking
Perfect	V-ing perfect
I must not have croaked you must not have croaked he must not have croaked we must not have croaked you must not have croaked they must not have croaked	I must not have been croaking you must not have been croaking he must not have been croaking we must not have been croaking you must not have been croaking they must not have been croaking

Interrogative form

Simple form	V-ing form
must I croak? must you croak? must he croak? must we croak? must you croak? must they croak?	must I be croaking? must you be croaking? must he be croaking? must we be croaking? must you be croaking? must they be croaking?
Perfect	V-ing perfect
must I have croaked? must you have croaked? must he have croaked? must we have croaked? must you have croaked? must they have croaked?	must I have been croaking? must you have been croaking? must he have been croaking? must we have been croaking? must you have been croaking? must they have been croaking?

Interro-negative form

Simple form	V-ing form
must I not croak? must you not croak? must he not croak? must we not croak? must you not croak? must they not croak?	must I not be croaking? must you not be croaking? must he not be croaking? must we not be croaking? must you not be croaking? must they not be croaking?
Perfect	V-ing perfect
must I not have croaked? must you not have croaked? must he not have croaked? must we not have croaked? must you not have croaked? must they not have croaked?	must I not have been croaking? must you not have been croaking? must he not have been croaking? must we not have been croaking? must you not have been croaking? must they not have been croaking?