reply

Compared meaning: to say or respond with words (verb).

比较义项：用言语说出信息或做出回应（动词）。

• reply 本词

  Reply specifically answers something already said, written or asked, usually paired with 'to' (reply to an email); it cannot take a person as a direct object.

  reply专指针对别人已经说过、写过或提出的内容作出回应，通常与“to”连用（如reply to an email），不能直接接人作宾语。

  Please reply to my email as soon as possible.

  请尽快回复我的邮件。

• say

  Say is the most general verb for putting words into speech or writing; it takes a direct quote or clause, but never a personal object (you cannot 'say someone').

  say是最普通的表达话语的动词，指把话说出来或写出来，后面可接直接引语或从句，但绝不能直接接人作宾语（不能说“say someone”）。

  Did she say what time the meeting starts?

  她说了会议几点开始吗？

• explain

  Explain focuses on making something complicated clear, often followed by how/why/what plus a clause; it describes or clarifies rather than simply passing on words.

  explain侧重把复杂或不易理解的事情讲清楚，后面常接how/why/what引导的从句，强调解释说明，而不只是传达话语。

  Can you explain how this machine works, please?

  你能解释一下这台机器是怎么运作的吗？

• tell

  Tell always needs a listener as its object (tell someone something); it emphasizes giving information or instructions directly to a person, not just uttering words.

  tell总是需要一个听话人作宾语（tell someone something），强调把信息或指示直接告诉某个人，而不只是单纯地说话。

  Please tell me what happened at the meeting.

  请告诉我会议上发生了什么事。

All four verbs mean to express words. Reply answers something already said; say is the plain, general word for speaking; explain makes something clear; tell always needs a listener, as in tell someone something. Tell's "know the difference" sense and say's "written" sense are excluded.

这四个词都表示“用言语表达或传递信息”，但对象和语法搭配不同：reply侧重针对别人说过或写过的内容作出回应，say只是单纯地说出话语，explain强调把复杂的事情讲清楚，tell则必须带一个听话人作宾语。这里不比较tell的“分辨，识别”（如tell the difference）以及say表示“（文字上）写着”的用法。

Compared meaning: a spoken or written reply to something (noun).

比较义项：回答、答复（名词）。

• response

  The broadest and most formal term; can describe any reaction to a situation, action, or event, not only a reply in words, and is common in official or written contexts.

  语气最正式、含义最广的词；可以指对情况、行动或事件的任何反应，不限于用语言作出的回答，常用于正式或书面语境。

  The government's response to the flooding was criticized as too slow.

  政府对这场洪灾的反应被批评为过于迟缓。

• answer

  The most basic and direct term, used mainly for a reply to a question, especially one with a single correct solution; plain and factual in tone.

  最基本、最直接的词，主要用于对问题的回答，尤指有唯一正确解的问题；语气平实、注重事实。

  She finally worked out the answer to the math problem.

  她终于算出了这道数学题的答案。

• reply 本词

  Used specifically for responding in kind to a message, letter, or spoken remark; implies direct interaction between two people rather than a reaction to an event.

  专指对书信、邮件或口头话语作出的相应回应；强调双方之间的直接互动，而不是对某一事件的反应。

  He still hasn't written a reply to his grandmother's letter.

  他还没有给奶奶的来信写回复。

All three nouns mean a reply to something. Response is the broadest, most formal term, covering any reaction, not just words. Answer is the most basic term, mainly for a reply to a question. Reply answers a letter, email, or remark, suggesting direct interaction.

这三个词都可以表示对某事的回答或反应，但语气和正式程度不同：response 语气最正式、含义最广，可以指对情况或事件的任何反应，不限于用语言作出的回答；answer 是最基本、最常用的词，尤指对问题给出的具体、正确的答案；reply 强调对书信、邮件等交流作出的回应，暗示双方之间的直接互动。