About of the students in Grade Nine this year were born in the.A. three five; 1996.B. thre

问题补充：

About of the students in Grade Nine this year were born in the.

A. three five; 1996.

B. three fifths; 1990s

C. third fifth; 1997.

D. third fifths; 1990s

答案：

A. three five; 1996.

(答案→)B. three fifths; 1990s

C. third fifth; 1997.

D. third fifths; 1990s

解析：分数的构成为分子用基数词，分母用序数词，分子如果大于1，则分母序数词一般都用复数形式，故用排除法只能选B项。