顽强不屈

jǐn guǎn é guó de sǔn shī cǎn zhòng tā men de dǐ kàng què réng rán wán qiáng bù qū

尽管俄国的损失惨重，他们的抵抗却仍然顽强不屈。

Despite their fearful losses, Russian resistance remained tough and unbending.

tā men xíng chéng le qiè ér bù shě jiān rěn bù bá wán qiáng bù qū de jīng shén

他们形成了锲而不舍、坚忍不拔、顽强不屈的精神。

They develop perseverance, stamina and the indomitable spirit.