pull oneself up by one’s bootstraps的字面意思是“提着鞋带把自己提起来”，比喻为“重新振作”的意思。用于描绘不依靠他人，凭借自己的力量和努力重新振作起来改变不好的处境。

【例句】
Mace was attempting to pull himself up by his bootstraps. There was savage hatred in his eyes.
梅斯试图重新振作起来，眼里射出凶残、仇恨的光。

Pull yourself up by your bootstraps, lad, and be a man for yourself.
振作起来，伙计，为了你自己，勇敢一点。