English verb conjugation
COULD SMILE

Regular verb: smile - smiled - smiled

Affirmation

Simple form	V-ing form
I could smile you could smile he could smile we could smile you could smile they could smile	I could be smiling you could be smiling he could be smiling we could be smiling you could be smiling they could be smiling
Perfect	V-ing perfect
I could have smiled you could have smiled he could have smiled we could have smiled you could have smiled they could have smiled	I could have been smiling you could have been smiling he could have been smiling we could have been smiling you could have been smiling they could have been smiling

Negation

Simple form	V-ing form
I could not smile you could not smile he could not smile we could not smile you could not smile they could not smile	I could not be smiling you could not be smiling he could not be smiling we could not be smiling you could not be smiling they could not be smiling
Perfect	V-ing perfect
I could not have smiled you could not have smiled he could not have smiled we could not have smiled you could not have smiled they could not have smiled	I could not have been smiling you could not have been smiling he could not have been smiling we could not have been smiling you could not have been smiling they could not have been smiling

Interrogative form

Simple form	V-ing form
could I smile? could you smile? could he smile? could we smile? could you smile? could they smile?	could I be smiling? could you be smiling? could he be smiling? could we be smiling? could you be smiling? could they be smiling?
Perfect	V-ing perfect
could I have smiled? could you have smiled? could he have smiled? could we have smiled? could you have smiled? could they have smiled?	could I have been smiling? could you have been smiling? could he have been smiling? could we have been smiling? could you have been smiling? could they have been smiling?

Interro-negative form

Simple form	V-ing form
could I not smile? could you not smile? could he not smile? could we not smile? could you not smile? could they not smile?	could I not be smiling? could you not be smiling? could he not be smiling? could we not be smiling? could you not be smiling? could they not be smiling?
Perfect	V-ing perfect
could I not have smiled? could you not have smiled? could he not have smiled? could we not have smiled? could you not have smiled? could they not have smiled?	could I not have been smiling? could you not have been smiling? could he not have been smiling? could we not have been smiling? could you not have been smiling? could they not have been smiling?