num.四;四个人(或事物)的一组;得四分的一击;四人赛艇的全体成员;四人赛艇;
例句:
The blackbird's nest contained four eggs.
黑鹂巢里有四个蛋.
A square has four corners.
正方形有四个角.
It poured for four days.
下了四天倾盆大雨.