题目内容：

One fifth of the population here ( ) farm workers .填is are?

优质解答

are
例句
About one-third of the adult homeless population are veterans

追问：

只能用"are"吗？还是两个都能用，但are用的更多一些？

追答：

one fifth of the uninsured population is able to afford insurance 这是用单数的情况。 基本都用ARE。