We were discussing the necessity of employing more staff.

　　我們在討論是否需要雇用更多員工。

　　Air-conditioning is an absolute necessity in this climate.

　　這樣的氣候絕對需要有空調。

　　Most women, like men, work from economic necessity

　　與男人一樣，大部分女人也是出于經(jīng)濟原因而工作。

　　Water is a basic necessity of life.

　　生命離不開(kāi)水。

　　The population failed to understand the necessity for the war to go on.

　　人們不能理解那場(chǎng)戰爭再繼續下去有什么必要。