一、作主语

It’s said that 13 is an unlucky number.据说13是一个不吉利的数字。

The first is better than this.第一个比这个好。

The second is yours.第二个是你的。

Two thirds of the apples were bad.三分之二的苹果是坏的。

【比较】

①Two thirds of workers have their own cars.

三分之二的工人都有自己的车。（workers决定谓语用复数）

②Over 70% of the water has been polluted here.

超过70%的水域已被污染。（water 决定谓语动词用单数）