问题补充：
- In our school library, there a number of books on science and the number of them growing larger and larger.
A. is, are
B. has, are
C. have, is
D. are, is
答案：
A. is, are
B. has, are
C. have, is
(答案→)D. are, is
解析：a number of…许多的···修饰可数名词复数the number of…···的总数，作主语看做单数。There be句型表示“某地(或某时)存在有某人(或某物)，句中有若干个名词作主语，动词be常与后面主语中的第一个名词在数上一致。故选D
