英语的单选,谢谢,要正确的单项选择There quarters of the students in our class

英语的单选,谢谢,要正确的
单项选择
There quarters of the students in our class __ girls last term.
A.are b.is c.was d.were
The population of China is __ than that of any other country in the world.
A.more b.fewer c.larger d.smaller
My father never goes to work late,__?
A.does he b.doesn't he c.is he d.isn't he
Most of us know what should do ,but we always have a hard time __ it.
A.do b.to do c.doing d.dome