苦练

kǔ liàn shā dí běn shi

苦练杀敌本事

practise hard to master the military skill

qín xué kǔ liàn

勤学苦练

study diligently and practise hard

wǒ jìn lì kǔ liàn

我尽力苦练。

I trained as hard as I could.

tā kǔ liàn yǐ shǐ jì shù xián shú

他苦练以使技术娴熟。

He practised hard to perfect his technique.