There is agreement on the necessity of reforms. [+ of]

对改革的必要性已经达成了共识。

As soon as the necessity for action is over the troops must be withdrawn.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。

Most women, like men, work from economic necessity.

与男人一样，大部分女人也是出于经济原因而工作。

Some people have to lead stressful lifestyles out of necessity.

一些人迫于生计不得不过着紧张忙碌的生活。

Water is a basic necessity of life. [+ of]

生命离不开水。

...food, fuel and other daily necessities.

食物、燃料和其他日常必需品

The President pleaded that strong rule from the centre was a regrettable, but temporary necessity.

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。