他的兼职工作几乎无法维持他一个人的生活，更不用说养家了。

His part-time job could barely ___sustain him, let alone a family.

在昂贵的城市里，一份薪水可能不足以维持一个家庭。

A single salary might not be enough to ___sustain a household in an expensive city.

保护工作对于维持这一生态系统微妙的平衡至关重要。

Conservation efforts are crucial to ___sustain the delicate balance of this ecosystem.