问题补充：
Our school has a big library. There are about ten books in it.
A. thousand
B. thousands
C. thousand of
D. thousands of
答案：
(答案→)A. thousand
B. thousands
C. thousand of
D. thousands of
解析：句意：我们的学校有一个大图书管。那里面有1万本书。thousand前面有确切的数字，表示确定所指时，不用of,不加s，故选A
