问题补充：
. Which of the following is wrong?
This book is easy enough for .
A. a six-year-old child
B. a child of six years old
C. a child aged six
D. a six years old child
答案：
A. a six-year-old child
B. a child of six years old
C. a child aged six
(答案→)D. a six years old child
解析：可联系答.案.网客服索取。
