yóu yú / wèi néng / cān jiā / ēn shī / de / gào bié yí shì / wǒ / yì zhí / yǐn yǐ wéi hàn

由于未能参加恩师的告别仪式，我一直引以为憾。

Because I was unable to attend my mentor's farewell ceremony, I have always regarded it as a regret.