Here are a few options for a WordPress post tag description for “公用事業” (Public Utilities) in Traditional Chinese, ranging in tone and detail:

**Option 1 (Concise & General):**

> 維繫社會運作的基本服務，包括電力、供水、燃氣等。 (Basic services that support society’s operation, including electricity, water supply, gas, etc.)

**Option 2 (Slightly More Descriptive):**

> 涵蓋提供公眾電力、自來水、天然氣等基本設施及服務的行業。 (Encompassing industries that provide essential infrastructure and services to the public, such as electricity, water, and natural gas.)

**Option 3 (Emphasizing Regulation and Importance):**

> 指受政府監管，提供重要基礎設施與服務的行業，例如電力、供水、污水處理及燃氣供應，對於社會穩定及公民生活至關重要。 (Refers to industries regulated by the government that provide essential infrastructure and services, such as electricity, water supply, wastewater treatment, and gas supply, which are crucial for social stability and the lives of citizens.)

**Option 4 (For a Technical or Business-Oriented Site):**

> 關於公用事業，其發展、運營、法規、投資及相關市場分析的標籤。 (Tags relating to public utilities, their development, operation, regulations, investment, and relevant market analysis.)

**Which option is best depends on the context of your website and the target audience.** Consider:

* **Who is your audience?** Are they general readers, industry professionals, or investors?
* **What is the tone of your website?** Formal, informal, technical, etc.
* **What information do you want to convey?** Basic definition, regulatory aspects, economic considerations?

**How to enter this in WordPress:**

When you add the tag “公用事業” in the WordPress editor, you should find a section where you can add a description. Choose the option that best fits your needs, and input the selected description into that field. (Make sure your WordPress theme supports displaying tag descriptions – most do.)