问题
选择题
About _____________ of the students this year were born in the 1990s.
A．three five
B．three fifths
C．third fifths
D．third fifth
答案
B
题目分析：句意：今年大约有五分之三的的学生是20世纪90年代出生。在英语中的分数，分子用基数词，分母用序数词，当分子大于一时，分母用复数形式。所以选B。