In our school there a number of books on science and the number of them growing larger

问题补充：

In our school there a number of books on science and the number of them growing larger and larger.

A. is; are

B. are; is

C. are; are

D. is; is

答案：

A. is; are

(答案→)B. are; is

C. are; are

D. is; is

解析：句意:我们学校有很多关于科学的书，这些书的数量变得越来越大。a number of 很多的，大量的，修饰可数名词复数，在句子中作主语时，动词用复数；the number of ...的数量，在句子中作主语时，动词用单数。故选B。