related

Compared meaning: linked or joined to something else (adjective).

比较义项：某物与另一物有联系、被连接或附加在一起（形容词）。

• related 本词

  Marks a logical, causal, or family relationship between two things or people; used with to; abstract rather than physical, as in related topics or blood relatives.

  表示两个事物或人之间存在逻辑上、因果上或血缘上的关系；常与介词 to 连用；是抽象关系，而非物理连接，例如相关的话题，或有血缘关系的亲属。

  She's related to the mayor through her mother's side of the family.

  她和市长有亲戚关系，是她母亲那边的家族成员。

• connected

  Marks that two things are linked so information, power, or influence can pass between them; common for networks, devices, and systems; can be physical or abstract, fairly neutral in tone.

  表示两个事物相连，使信息、电流或影响可以在两者之间传递；常用于网络、设备和系统；可以是物理连接，也可以是抽象连接，语气比较中性。

  Make sure your phone is connected to the office Wi-Fi network.

  请确保你的手机已连接到公司的 Wi-Fi 网络。

• attached

  Marks that one physical or digital item is fastened, added, or fixed onto another, as with files, documents, or objects; the most literal sense, emphasizing an actual join.

  表示一件物品（实物或电子文件）被固定、添加或附加在另一件物品上，例如文件、文档或物体；是三者中语气最字面、最强调实际连接的说法。

  She attached a photo of the receipt to her expense report.

  她把收据的照片附在了报销单上。

Related, connected and attached all mean linked to something else. Related marks a logical or family link, often with 'to'. Connected marks a link that lets information pass. Attached marks a physical item fixed onto another. Not compared: attached's emotional sense, or connected's 'contacts' sense.

这三个词都表示某物与另一物有联系，但联系的性质和强度不同：related 侧重逻辑或血缘上的关联，connected 侧重两者之间信息或系统上的连接，attached 侧重实物或文件被固定、添加在一起，语气最直接、最字面。这里不比较 attached 表示依恋、喜爱的情感义（如对某人或宠物有感情），也不比较 connected 表示有人脉、关系广的引申义。