百折不挠
Fight for it tooth and nail.
Get at it hammer and tongs.
Never say die.
Stick it out.

eg：If Tom wants to win the scholarship, he has to fight for it tooth and nail in studying all text books.

中英俚语俗语来源：“汉·蔡邕有百折不挠，临大节而不可夺之风。”

同义词：不屈不挠 Firm and unyielding.
反义词：俯首就范 Give one's head for the washing.