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 can't croak you can't croak he can't croak we can't croak you can't croak they can't croak	I can't be croaking you can't be croaking he can't be croaking we can't be croaking you can't be croaking they can't be croaking
Perfect	V-ing perfect
I can't have croaked you can't have croaked he can't have croaked we can't have croaked you can't have croaked they can't have croaked	I can't have been croaking you can't have been croaking he can't have been croaking we can't have been croaking you can't have been croaking they can't 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't I croak? can't you croak? can't he croak? can't we croak? can't you croak? can't they croak?	can't I be croaking? can't you be croaking? can't he be croaking? can't we be croaking? can't you be croaking? can't they be croaking?
Perfect	V-ing perfect
can't I have croaked? can't you have croaked? can't he have croaked? can't we have croaked? can't you have croaked? can't they have croaked?	can't I have been croaking? can't you have been croaking? can't he have been croaking? can't we have been croaking? can't you have been croaking? can't they have been croaking?