English verb conjugation
COULD CONCERTINA

Regular verb: concertina - concertinaed - concertinaed

Affirmation

Simple form	V-ing form
I could concertina you could concertina he could concertina we could concertina you could concertina they could concertina	I could be concertinaing you could be concertinaing he could be concertinaing we could be concertinaing you could be concertinaing they could be concertinaing
Perfect	V-ing perfect
I could have concertinaed you could have concertinaed he could have concertinaed we could have concertinaed you could have concertinaed they could have concertinaed	I could have been concertinaing you could have been concertinaing he could have been concertinaing we could have been concertinaing you could have been concertinaing they could have been concertinaing

Negation

Simple form	V-ing form
I could not concertina you could not concertina he could not concertina we could not concertina you could not concertina they could not concertina	I could not be concertinaing you could not be concertinaing he could not be concertinaing we could not be concertinaing you could not be concertinaing they could not be concertinaing
Perfect	V-ing perfect
I could not have concertinaed you could not have concertinaed he could not have concertinaed we could not have concertinaed you could not have concertinaed they could not have concertinaed	I could not have been concertinaing you could not have been concertinaing he could not have been concertinaing we could not have been concertinaing you could not have been concertinaing they could not have been concertinaing

Interrogative form

Simple form	V-ing form
could I concertina? could you concertina? could he concertina? could we concertina? could you concertina? could they concertina?	could I be concertinaing? could you be concertinaing? could he be concertinaing? could we be concertinaing? could you be concertinaing? could they be concertinaing?
Perfect	V-ing perfect
could I have concertinaed? could you have concertinaed? could he have concertinaed? could we have concertinaed? could you have concertinaed? could they have concertinaed?	could I have been concertinaing? could you have been concertinaing? could he have been concertinaing? could we have been concertinaing? could you have been concertinaing? could they have been concertinaing?

Interro-negative form

Simple form	V-ing form
could I not concertina? could you not concertina? could he not concertina? could we not concertina? could you not concertina? could they not concertina?	could I not be concertinaing? could you not be concertinaing? could he not be concertinaing? could we not be concertinaing? could you not be concertinaing? could they not be concertinaing?
Perfect	V-ing perfect
could I not have concertinaed? could you not have concertinaed? could he not have concertinaed? could we not have concertinaed? could you not have concertinaed? could they not have concertinaed?	could I not have been concertinaing? could you not have been concertinaing? could he not have been concertinaing? could we not have been concertinaing? could you not have been concertinaing? could they not have been concertinaing?