n.需要；必需品；必然
Necessity is the mother of invention. 需要是发明之母。
Want and necessity break faiths and oaths. 匮乏和需要可以打破信仰和誓言。
Water is of vital necessity in the desert. 在沙漠地区水是维持生命的必需品。
Food is a necessity, but wine is an extravagance. 食物是必需品,而酒则是奢侈品。
That men would die was a matter of necessity; which men would die, though, was a matter of circumstance. 人总有一死，这是必然的事，不过哪些人死，这是偶然的事。
