为什么two fifths of the population后加are,而two fifths of the land后加is?不是population不可数的吗

为什么two fifths of the population后加are,而two fifths of the land后加is?不是population不可数的吗 Two fifths of the building was destroyed in the fire为什么 用 was 而不用 were Two fifths of the building was destroyed in the fire为什么用 was 而不用 were Two fifths of the books are sold out 中文意思 _____ of the land in that district_____ covered with trees and grass.A.Two fifth;isB.Two fifth;areC.Two fifths;isD.Two fifths;are请选出答案并说明为什么这样选,有什么语法根据! ______ of the students took part in the reading contest yesterday afternoon.A.Two-fifth B.Two fifths C.Two fifth D.Two-fifths ______ of the land in that district ______ covered with trees and grassA.Two fifth; is B.Two fifth; areC.Two fifths; is D.Two fifths; are 关于主谓一致的 并说说为什么_____ of the land in that district _____ covered with trees and grass.A.Two fifth,is B.Two fifth,areC.Two fifths,is D.Two fifths ,are Between then two rows of trees _____ the teaching building.A.stand B.stands To our joy,________________-To our joy,________________1.two-fifth of the work has been finished2.two-fifths of the work have been finished3.two-fifth of the work have been finished4.two-fifths of the work has been finished 17._________of the population in the city come from other provinces这个选B为什么.具体的意思是什么A.Two fifths B.Two fifth C.Second fifths Two fifths of the land in that district ( ) covered with trees and trees and grass. Two fifths of the land iin that country ____covered with trees and grassA are B is ( )of the students in our class( _ )interested in micro blogs(微博)on the Internet A Two fifths; is B Two fifths areC.Two five is D Two-five are 4.The stone is about ___ the size of a basketball.A.two fifth B.two fifths C.two five D.two fives About( ) of the students in our school took part in the school sports meeting last fridayA.one-thirds B.two-thirds C.one-fifths D.two-thirds标准答案是d,我也不知道是为什么, ._____ of the land in that district _____ Covered with trees and grass.A.Two fifth; is B.Two fifth; are C.Two fifths; is D.Two fifths; are为什么是C? 3.___ of the land in that district ___ covered with trees and grass.A Two fifth, is B Two fifths,is我只想知道 Two fifth, Two fifths 两个的区别,含义~ 1. ____ of the land in this district _______ covered with trees and grass.A. Two fifths; are B. Two fifth; arec. Two fifth; is D.Two fifths; is 写原因,最好详细一点