two-thirds of a cake 后的谓语动词是单数还是复数?

问题描述:

two-thirds of a cake 后的谓语动词是单数还是复数?

单数.分数,百分之. 后面的谓语动词用单数还是复数,由其后的名词决定.
75% of the students here are from China.(students是复数名词,故用复数动词are)
Three quaters of the land is polluted.(land是不可数,故用单数动词is)