necessitate/necessity

necessitate /niˈsesiteit/ vt. 使成为必要/需要：The increase in population necessitates a greater food supply. 人口的增加需要更多的食品供应。

 necessity /niˈsesiti/ n. 1.［u］必要(性)，(迫切)需要: There’s no necessity to hurry. 没有必要匆忙。You can dial directly without the necessity to go/of going through the operator.你可以直接拨打，没有必要通过总机。Necessity is the mother of invention.［谚］ 需要是发明之母。of necessity 势必，必定，不可避免地：The visit will, of necessity, be brief.访问时间势必会很短暂。out of necessity出于必要：He is changing job out of necessity, not because he particularly wants to.他不得已才换工作，并非是自己特别愿意。2.［c］必需品: lack the basic necessities of life 缺少基本的生活必需品Food and clothing are necessities of life. 衣食是生活必需品。