问题补充：
I study in High School Affiliated to Southwest University. There are students in our school. Nine of them are girls.
A. thousands of; hundred
B. thousand of; hundreds
C. thousand of; hundred
D. thousands of; hundreds
答案：
(答案→)A. thousands of; hundred
B. thousand of; hundreds
C. thousand of; hundred
D. thousands of; hundreds
解析：此题考查名词的量。确切数量常用数词+hundred/thousand/million/billion+名词的复数形式；不确切数量常用hundreds/thousands/millions/billions + of+名词的复数形式.
