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. are; is
C. is; is
D. are; are
答案:
A. is; are
(答案→)B. are; is
C. is; is
D. are; are
解析:a number of一些,许多;the number of……的数目。句意:我们学校图书馆有许多有关科学的书籍,并且他们的数目变得越来越大。结合语境可知前文主语为复数形式,故系动词用复数。下文主语number表示抽象含义,故谓语动词用单数,选B。