「於事無補 / 無補於事」

(pos:語句)
<explanation>
yue:喺一件事上面做咩都唔能夠改變結果
eng:regardless of what one does, the outcome of a matter will remain unchanged; futile
<eg>
yue:人都死咗咯，你怪責自己都於事無補㗎啦。 (jan4 dou1 sei2 zo2 lok3, nei5 gwaai3 zaak3 zi6 gei2 dou1 jyu1 si6 mou4 bou2 gaa3 laa1.)
eng:You couldn't revive the dead even if you drowned yourself with guilt.