quantity

Compared meaning: an amount or quantity of something (noun).

比较义项：数量（名词）。

• amount

  More general and informal; typically pairs with uncountable nouns (time, money, effort) and is vague about precise measurement.

  更笼统、更口语化；通常与不可数名词（时间、金钱、精力）搭配，不强调精确的测量。

  She spent a large amount of time studying for the exam.

  她花了大量时间准备考试。

• quantity 本词

  More formal and precise, often used with countable or measurable nouns in technical, scientific or commercial contexts.

  更正式、更精确，常与可计数或可测量的名词搭配，多用于技术、科学或商业语境。

  We need a large quantity of paper for the printing project.

  这个印刷项目我们需要大量的纸张。

Amount and quantity both mean how much of something there is, and are often interchangeable. Quantity is more formal, used for precise, countable, or measurable things. Amount is more general and informal, often used with uncountable nouns like time, money, or effort.

amount 和 quantity 在“数量”这个义项上很接近，常可互换，但 quantity 更正式、更常用于精确或可计数、可测量的语境，而 amount 更笼统、多与不可数名词搭配。这里不比较其他义项。