这几乎是世界人口的五分之一。

That's almost one fifth of the world's population.

这个蛋糕被吃掉了五分之一。

One fifth of the cake was eaten.

他捐出了他收入的五分之一。

He donated one fifth of his income.

这本书的五分之一是关于历史的。

One fifth of this book is about history.

这个班级的学生五分之一是女生。

One fifth of the students in this class are girls.

这个国家五分之一的人口是老年人。

One fifth of the population in this country are elderly.

五分之一等于百分之二十。

One fifth is the same as 20 percent.

五分之一加仑或一夸脱酒的五分之四

One fifth of a gallon OR four fifths of a quart of liquOR.

五分之一加仑或一夸脱酒的五分之四.

One fifth of a gallon or four fifths of a quart of liquor.

五个人分那块糕,每人分得五分之一.

Each of the five people had one fifth of the cake.