decline

Compared meaning: to say no to something (verb).

比较义项：拒绝（做某事／接受某事）（动词）。

• refuse

  The most general, everyday word for saying no to doing or accepting something; can sound blunt or forceful, and is the only one that pairs naturally with strong demands or orders.

  语气最直接、最生硬的「拒绝」，可以很强硬，常用于拒绝做某事，或拒绝接受强硬的要求、命令。

  The soldiers refused to obey the order and were arrested on the spot.

  士兵们拒绝服从命令，当场被逮捕。

• decline 本词

  A polite, formal way to refuse, especially invitations, offers or requests; softer in tone than refuse, and unrelated to decline's other everyday meaning of decreasing.

  一种礼貌、正式的「婉拒」方式，尤其用于回绝邀请、提议或请求，语气比 refuse 柔和（与 decline 另一个表示「下降、减少」的意思无关）。

  She politely declined the invitation, explaining she already had plans that evening.

  她礼貌地婉拒了邀请，解释说她那天晚上已经有安排了。

• reject

  To formally refuse to accept something after consideration, typically an application, proposal or idea; takes only a noun object, never an infinitive, and often sounds official or blunt.

  经过考虑后正式地不予接受，通常用于申请、提案等场合，只能接名词宾语（不能说 reject to do something），语气常显得正式或生硬。

  The committee rejected his proposal because it exceeded the approved budget.

  委员会驳回了他的提案，因为超出了批准的预算。

Refuse, decline, and reject all mean to say no. Refuse is the general, everyday word, sometimes blunt. Decline is a polite, formal way to refuse, especially invitations. Reject means to formally turn down something, like an application. It does not cover decline's meaning to decrease.

这三个词都表示「拒绝」，但语气和场合不同：refuse 语气最直接甚至强硬，可用于拒绝做某事或拒绝接受某物；decline 语气委婉客气，常用于礼貌地回绝邀请、提议或请求；reject 强调经过考虑后正式地不予接受，常用于申请、提案等场合，语气较为正式或生硬。这里不比较 decline 表示「下降、减少」的义项（如原例句 Sales began to decline sharply 中的用法）。

Compared meaning: to become worse (verb).

比较义项：变差、下降（动词）。

• decline 本词

  Decline describes a gradual, often measurable decrease in amount, quality, or value; it is typically used with numbers, sales, population, or health rather than abstract problems.

  decline指数量、质量或价值的逐渐下降，通常是可衡量的，常用于数字、销售额、人口或健康状况，而不是抽象的问题。

  The town's population has declined steadily since the factory closed.

  自从那家工厂关闭以来，这座小镇的人口一直在稳步下降。

• worsen

  Worsen means a situation, condition, or problem is becoming more severe or serious, often used with illnesses, weather, or problems, and can happen quickly rather than gradually.

  worsen指某种情况、状况或问题变得更严重、更糟糕，常用于疾病、天气或问题，而且可能来得很快，不一定是逐渐发生的。

  The weather forecast says the storm will worsen by evening.

  天气预报说，这场风暴到傍晚会恶化。

Decline and worsen both mean to become worse. Decline suggests a gradual, measurable decrease, often used with sales, numbers, or health. Worsen means something is becoming more serious, often with illness or weather, and can happen fast. It does not cover decline meaning to refuse.

decline和worsen在“变差、下降”这个意义上很接近，但decline更强调数量、质量或价值的逐渐下降，常用于销售额、人口等可衡量的对象；worsen更强调情况或问题变得更严重，常用于疾病、天气等，语气上更强烈，也可能来得很突然。这里不比较decline表示“婉拒，谢绝”的意思。