逼出來的、不得不做
把清單上的壓力放到行動上：不是你選的，是情況把路都堵住了，只剩這一條。這裡帶著一點無奈，用的人通常是在解釋自己為什麼這樣做。
necessity (unavoidable duty) · noun · B2
Something that must happen or must be done, even when you do not like it.
不得不做的事；無奈之舉
核心畫面
Picture packing a bag and going through it twice: the things you would like to bring can come out, but a few things stay in no matter what — you simply cannot go without them. Necessity is that short list, and the pressure behind it: not what you want, but what there is no way around.
可以想成：整理行李時再檢查一遍，想帶的東西可以拿出來，但有幾樣不管怎樣都得留在裡面，少了就是不行。necessity…更多收起
可以想成：整理行李時再檢查一遍，想帶的東西可以拿出來，但有幾樣不管怎樣都得留在裡面，少了就是不行。necessity 講的就是那份短短的清單，以及背後那股「沒有別的辦法」的壓力——重點不在想不想要，而在繞不過去。From the picture
只活在固定說法裡
這一支不是 necessity 單獨的新意思，而是兩個固定說法把它包在裡面。學的時候要整串記，拆開來單用是不通的。
of necessity · noun · C1
Used in the phrase of necessity to say that something happens in the only way it can happen.
必然地；不得不（of necessity）
Also in this word
necessity (essential item) · noun · B1
Something you must have in order to live, work, or do something important — not just for fun.
必需品
necessity (being needed) · noun · B2
The fact that something is needed, or that someone must do it.
必要性；需要
原始詞典資料7 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。
necessitynoun/nɪˈsɛsəti/
- 1
The quality or state of being necessary, unavoidable, or absolutely requisite.
- I bought a new table out of necessity. My old one was ruined.
- Educating the public about some of the myths that underlie their fears that non-traditional families will of necessity be detrimental to the well-being of foster children.
- 2
The condition of being needy; desperate need; lack.
- For it is in vain for a man to think to seek God in his necessity and exigence, if he seek not God in his ordinances, and do not joy in them.
- 3
Something necessary; a requisite; something indispensable.
- A tent is a necessity if you plan on camping.
- Look for the bare necessities / The simple bare necessities / Forget about your worries and your strife
- 4
Something which makes an act or an event unavoidable; an irresistible force; overruling power.
- After eating a full meal, the human body's necessity for food will compel the person to eat again in the future.
- I stopped, and said with inly muttered voice, 'It doth not love the shower, nor seek the cold: This neither is its courage nor its choice, But its necessity in being old.
- 5
The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism.
- 6
lawGreater utilitarian good; used in justification of a criminal act.
- doctrine of necessity
- 7
lawIndispensable requirements (of life).
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。