English verb conjugation
MUST CROAK

Regular verb: croak - croaked - croaked

Affirmation

Simple form	V-ing form
I must croak you must croak she must croak we must croak you must croak they must croak	I must be croaking you must be croaking she 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 she 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 she 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 mustn't croak you mustn't croak she mustn't croak we mustn't croak you mustn't croak they mustn't croak	I mustn't be croaking you mustn't be croaking she mustn't be croaking we mustn't be croaking you mustn't be croaking they mustn't be croaking
Perfect	V-ing perfect
I mustn't have croaked you mustn't have croaked she mustn't have croaked we mustn't have croaked you mustn't have croaked they mustn't have croaked	I mustn't have been croaking you mustn't have been croaking she mustn't have been croaking we mustn't have been croaking you mustn't have been croaking they mustn't have been croaking

Interrogative form

Simple form	V-ing form
must I croak? must you croak? must she croak? must we croak? must you croak? must they croak?	must I be croaking? must you be croaking? must she 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 she 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 she 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
mustn't I croak? mustn't you croak? mustn't she croak? mustn't we croak? mustn't you croak? mustn't they croak?	mustn't I be croaking? mustn't you be croaking? mustn't she be croaking? mustn't we be croaking? mustn't you be croaking? mustn't they be croaking?
Perfect	V-ing perfect
mustn't I have croaked? mustn't you have croaked? mustn't she have croaked? mustn't we have croaked? mustn't you have croaked? mustn't they have croaked?	mustn't I have been croaking? mustn't you have been croaking? mustn't she have been croaking? mustn't we have been croaking? mustn't you have been croaking? mustn't they have been croaking?