问题补充：
About 56 people live in this country.
A. million
B. millions
C. a million of
D. millions of
答案：
(答案→)A. million
B. millions
C. a million of
D. millions of
解析：此题考查名词的量。确切数量常用数词+hundred/thousand/million/billion+名词的复数形式；不确切数量常用hundreds/thousands/millions/billions + of+名词的复数形式.根据语境可知选择A。
