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 couldn't smile you couldn't smile he couldn't smile we couldn't smile you couldn't smile they couldn't smile	I couldn't be smiling you couldn't be smiling he couldn't be smiling we couldn't be smiling you couldn't be smiling they couldn't be smiling
Perfect	V-ing perfect
I couldn't have smiled you couldn't have smiled he couldn't have smiled we couldn't have smiled you couldn't have smiled they couldn't have smiled	I couldn't have been smiling you couldn't have been smiling he couldn't have been smiling we couldn't have been smiling you couldn't have been smiling they couldn't 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
couldn't I smile? couldn't you smile? couldn't he smile? couldn't we smile? couldn't you smile? couldn't they smile?	couldn't I be smiling? couldn't you be smiling? couldn't he be smiling? couldn't we be smiling? couldn't you be smiling? couldn't they be smiling?
Perfect	V-ing perfect
couldn't I have smiled? couldn't you have smiled? couldn't he have smiled? couldn't we have smiled? couldn't you have smiled? couldn't they have smiled?	couldn't I have been smiling? couldn't you have been smiling? couldn't he have been smiling? couldn't we have been smiling? couldn't you have been smiling? couldn't they have been smiling?