[求助]求助，来源：刘易斯讲义

Africa's black rhino population in the mid-1070's nunbered about 2000, ten times the estimated population of 200 in 1997.

a the estimated population
    

b that of their estimated population

c more then the population's estimated amount

d more black rhinos than their population estimate

e more than that of their population's estimated amount

觉得a怎么都怪怪的，a是正确答案

XXX times 后面可以加名词呀

比如 A is three times the length of B.

我新东方的班也是和刘易斯学的