【关于英语单复数的两个问题急threefifthsofthepopulation后面的be动词形式是用is还是are?threefifthsofthepeople后面的be动词用复数还是单数?】

　　关于英语单复数的两个问题急

　　threefifthsofthepopulation后面的be动词形式是用is还是are?

　　threefifthsofthepeople后面的be动词用复数还是单数?