number of the students in their school is about two thousand of them are boys.A. A; two

问题补充：

number of the students in their school is about two thousand, of them are boys.

A. A; two thirds

B. The; two third

C. The; two thirds

D. A; two third

答案：

A. A; two thirds

B. The; two third

(答案→)C. The; two thirds

D. A; two third

解析：句意为：他们学校学生的数量大约2000人。其中2/3是男孩。the number of+名词复数，指“……的数量”，a number of+名词复数，表示“许多的”“大量的”。分数的表达：分子用基数词，分母用序数词，当分子大于1时，序数词加“s”。结合选项可知应选C。