I could warn you could warn he could warn we could warn you could warn they could warn
Forme en V-ing
I could be warning you could be warning he could be warning we could be warning you could be warning they could be warning
Perfect
I could have warned you could have warned he could have warned we could have warned you could have warned they could have warned
Perfect en V-ing
I could have been warning you could have been warning he could have been warning we could have been warning you could have been warning they could have been warning
Négation
Forme simple
I could not warn you could not warn he could not warn we could not warn you could not warn they could not warn
Forme en V-ing
I could not be warning you could not be warning he could not be warning we could not be warning you could not be warning they could not be warning
Perfect
I could not have warned you could not have warned he could not have warned we could not have warned you could not have warned they could not have warned
Perfect en V-ing
I could not have been warning you could not have been warning he could not have been warning we could not have been warning you could not have been warning they could not have been warning
Forme interrogative
Forme simple
could I warn? could you warn? could he warn? could we warn? could you warn? could they warn?
Forme en V-ing
could I be warning? could you be warning? could he be warning? could we be warning? could you be warning? could they be warning?
Perfect
could I have warned? could you have warned? could he have warned? could we have warned? could you have warned? could they have warned?
Perfect en V-ing
could I have been warning? could you have been warning? could he have been warning? could we have been warning? could you have been warning? could they have been warning?
Forme interro-négative
Forme simple
could I not warn? could you not warn? could he not warn? could we not warn? could you not warn? could they not warn?
Forme en V-ing
could I not be warning? could you not be warning? could he not be warning? could we not be warning? could you not be warning? could they not be warning?
Perfect
could I not have warned? could you not have warned? could he not have warned? could we not have warned? could you not have warned? could they not have warned?
Perfect en V-ing
could I not have been warning? could you not have been warning? could he not have been warning? could we not have been warning? could you not have been warning? could they not have been warning?