There are about students in the school and of them are boys.A. two thousand three fif

问题补充：

There are about students in the school, and of them are boys.

A. two thousand, three fifth

B. two thousand, three fifths

C. two thousands, three fifths

答案：

解析：句意为：这所学校大约有两千学生，3/5是男生。当hundred/thousand/million等词前有确切数字时，hundred/thousand/million等词后不加s，且无of，当hundred/thousand/million等词前无确切数字时，hundred/thousand/million等词后加s，且有of。分数的表达：分子用基数词，分母用序数词，当分子大于1时，分母应加s。结合选项可知应选B。