Here are a few options for a WordPress post tag description for “auxiliary verb” in Traditional Chinese (助動詞 – Zhùdòngcí), depending on the desired level of detail and target audience:

**Option 1: Concise & Informative (Good for general use)**

* **Title:** 助動詞 (Zhùdòngcí)
* **Description:** 文章中使用，幫助主要動詞表達語氣、時態或情態的詞語。
* (Translation: Words used in the article to help the main verb express mood, tense, or modality.)

**Option 2: Slightly More Detailed (Suitable for language learners)**

* **Title:** 助動詞 (Zhùdòngcí)
* **Description:** 又稱為「助詞」，為動詞的輔助，主要用於修飾句子的語氣、時態或情態，例如「可以」、「應該」、「會」等。
* (Translation: Also known as “auxiliary particles,” they assist verbs, primarily used to modify the mood, tense, or modality of sentences, such as “can,” “should,” “will,” etc.)

**Option 3: Emphasizing the Function (Focusing on how they are used)**

* **Title:** 助動詞 (Zhùdòngcí)
* **Description:** 用來描述動作的狀態，表達可能性、必要性、意願，以及其他語氣的詞語，與主要動詞相互配合，組成更完整的句子。
* (Translation: Words used to describe the state of actions, expressing possibilities, necessities, intentions, and other moods, working with main verbs to form more complete sentences.)

**Option 4: A Bit More Technical (for grammar/linguistics-focused blog)**

* **Title:** 助動詞 (Zhùdòngcí)
* **Description:** 屬於動詞的一種，但無實質動作意義，而是用來表示語氣、時態、情態或語氣的詞類。通常位於主要動詞之前。
* (Translation: A type of verb, but without the meaning of a real action, instead used to indicate mood, tense, modality or other grammar functions. Usually placed before the main verb.)

**Key Considerations when Choosing:**

* **Your Audience:** Who are you writing for? Beginner language learners, native speakers, or grammar enthusiasts?
* **Blog Content:** What kind of content does your blog feature? Adjust the description’s technicality to suit.
* **Keyword Optimization:** Consider including related keywords in the description.

I recommend to use option 2 or 3 because these strikes a good balance between clarity and helpful information. Choose the one that best fits your target audience and the overall tone of your blog.