English verb conjugation
CAN CROAK

Regular verb: croak - croaked - croaked

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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