问题补充：
About of the books in our school library written in English.
A. one-fifth, are
B. one-fifths, is
C. one-fifth, is
D. first-fifth, are
答案：
(答案→)A. one-fifth, are
B. one-fifths, is
C. one-fifth, is
D. first-fifth, are
解析：
试题分析: 句意：我们校图书馆五分之一的书是用英语写的。分数用基本数词表示分子，序数词表示分母，分母大于1时分母加s; books书，可数名词复数，其谓语动词为复数，故选A
