miàn / duì / bù / gōng / de / dài / yù / ， / tā / zhǐ / néng / cháng / gē / dàng / kū / ， / shū / fā / xīn / zhōng / de / fèn / mèn / 。

面对不公的待遇，他只能长歌当哭，抒发心中的愤懑。

Faced with unfair treatment, he could only sing to vent his indignation and express the resentment in his heart.