improvement

Compared meaning: progress, a positive change (noun).

比较义项：变得更好的进步、改善（名词）。

• improvement 本词

  The general, everyday word for any change for the better - skills, health, performance or quality; used in both casual and formal contexts.

  improvement是通用词，指任何变得更好的变化——技能、健康、表现、质量等方面都可以用，口语和正式场合皆适用。

  She's made real improvement in her tennis serve since taking lessons.

  自从上课以来，她的网球发球有了真正的进步。

• advance

  Refers to significant progress or a breakthrough, especially in science, technology or a field of knowledge; more formal, often used in the plural (advances).

  advance指某一领域（尤其是科学、技术）中的重大进展或突破，语气更正式，常用复数形式advances。

  The new vaccine represents a major advance in the fight against malaria.

  这种新疫苗代表着抗击疟疾斗争中的一大进展。

Both words mean a change for the better, but usage differs. Improvement is the everyday word for progress in skills, health or performance. Advance is formal, meaning major progress or a breakthrough in science or technology, used as 'advances'. Advance's other meanings are not compared.

这两个词在“变得更好”这个意义上很接近，但语气和使用场合不同：improvement是日常通用词，技能、健康、表现等方面的进步都可以用；advance更正式，多指科学、技术等领域中的重大进展或突破，常用复数advances。这里不比较advance的其他意思，例如“预付款”或习语in advance（提前，如原例句中的订票场景）。