necessity经典引文

1. [U]必要(性); (迫切)需要 circumstances that force one to do sth; state of being necessary
2. [C]必需品 necessary thing
3. [S]自然规律 natural law that is seen as governing human action

1.必然;必要
Thenecessity of something is the fact that it must happen or exist.

e.g. There is agreement on thenecessity of reforms...
对改革的必要性已经达成了共识。
e.g. As soon as thenecessity for action is over the troops must be withdrawn...
一旦军事行动的必要性不复存在，军队就必须撤出。

2.必需品;必不可少的事物
Anecessity is something that you must have in order to live properly or do something.

e.g. Water is a basicnecessity of life.
生命离不开水。
e.g. ...food, fuel and other daily necessities.
食物、燃料和其他日常必需品

3.不可避免的情况(或行动)
A situation or action that is anecessity is necessary and cannot be avoided.

e.g. The President pleaded that strong rule from the centre was a regrettable, but temporarynecessity.
总统辩解说，实行高度的中央集权虽不尽如人意，但暂时来说却是必要的。

1. You must understand the necessity of education.
   你必须懂得教育的必要性。
2. There is no necessity to buy tickets in advance.
   没有必要提前买票。
3. He was forced by necessity to steal a loaf of bread.
   他为生活所迫偷了一块面包。
4. Most athletes can see the necessity of〔for〕 keeping training.
   大多数运动员都明白坚持训练的必要性。
5. Telephone is now a household necessity.
   现在电话是一种家庭必需品。

of necessity

必然,不可避免地necessarily; unavoidably