in attendance 的兩個固定說法
這兩條都不能拆，只活在 in attendance 這個結構裡，語氣都很正式：一個是「在場」，加上 on 之後就變成「隨侍在某人身邊」。
be in attendance · noun · C1
in the phrase 'be in attendance': to be at a special or important event.
出席（正式場合）
核心畫面
The noun of attend: being there. From that one idea English takes two directions — count the people who were there and you get a figure, or keep the older flavour of attend (waiting on someone) and you get the formal phrases about who was present at an event, and who stayed by an important person's side.
這是動詞 attend 的名詞：人到場了。從這一個概念，英文往兩邊走——把到場的人數一數，就成了一個數字；保留 at…更多收起
這是動詞 attend 的名詞：人到場了。從這一個概念，英文往兩邊走——把到場的人數一數，就成了一個數字；保留 attend 比較老的那層味道（隨侍、伺候），就成了那兩個正式說法：誰出席了那個場合，以及誰一直陪在重要人物身邊。From the picture
Also in this word
attendance, going regularly · noun · B1
the act of going to a place such as a school, a class, or a meeting, or how often you go there.
出席；到課
attendance, turnout · noun · B1
the number of people who go to an event such as a game, a concert, or a meeting.
出席人數；到場人數
原始詞典資料5 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
attendancenoun/əˈtɛn.dəns/
- 1
The act of attending; the state of being present; presence.
- Attendance at the meeting is required.
- All those in attendance are to sign this slip.
- 2
A tally or listing of the persons present.
- The class sat down so that the teacher could take attendance.
- The workshop […] was extremely successful with an attendance of more than 380 participants from government, the private sector and members of Trade Associations for Grains, Seed and Cocoa Federation.
- 3
The frequency with which one has been present for a regular activity or set of events.
- John's attendance for the conventions was not good.
- 4
obsoleteAttention paid to something; careful regard.
- The matter required his immediate attendance.
- 5
Maid service.
- "And what are you going to charge me?" There had come a kindly, almost a friendly note into his voice. "With attendance, mind! I shall expect you to give me attendance, and I need hardly ask if you can cook, Mrs. Bunting?"
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。