從圈外進來的東西
這一支就是核心畫面本身，講的是來源。
adjective · C1
Coming from outside the thing itself and not part of it — used about noise, light, heat, and material that has got into something where it does not belong.
外來的
核心畫面
One way to hold this word: draw a circle around the thing you care about — this recording, this question, this sample — and extraneous is whatever came in from outside that circle. It does not say the thing is bad. It says it is from elsewhere.
這個字可以想成先在你關心的東西外面畫一個圈：這段錄音、這個題目、這份樣本。從圈外跑進來的，就是 extraneous…更多收起
這個字可以想成先在你關心的東西外面畫一個圈：這段錄音、這個題目、這份樣本。從圈外跑進來的，就是 extraneous。它不是說那樣東西不好，而是說它來自別的地方。From the word’s history
Wiktionary gives extraneous as from Latin extrāneus, 'from without, strange', and notes it is a doublet of strange. The outside-the-circle picture is the word's oldest meaning, not a modern extension.
根據 Wiktionary，extraneous 來自拉丁文 extrāneus，意思是「從外面來的、陌生的」，而且它和 strange 是同源的一對。所以「圈外來的」這個畫面，本來就是這個字最早的意思，不是後來才加上去的。
Wiktionary entry 'extraneous' (packet source_ref kaikki:3f6f69a190036ae4:640987306:12742), etymology_text
Two branches
不在這一題裡，所以是多餘的
把那個圈從一件實體的東西換成一個題目或一個問題。一樣是「圈外來的」，只是這次圈的是討論的範圍，所以結論變成「用不到」。
adjective · C1
Not connected with the subject or problem you are dealing with, and therefore not needed — used about details, information, facts and matter that get in the way.
無關的；多餘的