15. Nous regrettions d’avoir promis

15. Nous regrettions d’avoir promis d’assister à sa conférence.
16. Il regrette de ne pas savoir jouer aux échecs.

Kết quả (Anh) 1:

15. We regret of having promised to attend its conference.16. He regretted not knowing play chess.

Kết quả (Anh) 2:

15. We regret to have promised to attend the conference.
16. He regrets not know how to play chess.

Kết quả (Anh) 3:

15. We regret to have promised to attend at its conférence.
16. He regretted not know play to échecs.