关于主谓一致的 并说说为什么_____ of the land in that district _____ cover

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,are
C.Two fifths,is D.Two fifths ,are
Between then two rows of trees _____ the teaching building.
A.stand B.stands C.standing D.are
22.All that can be done______.
A.has been done B.has done
C.have done D.were done
23.They each _____ a new dictionary.
A.has B.have C.is D.are
24.The singer and the dancer ______ come to the meeting.
A.has B.have C.are D.is
25.I have finished a large part of the book; the rest _____more difficult.
A.is B.are C.was D.were