问题补充:
The boy is playing chess with his grandfather.
A. 8-years-old
B. 8 years old
C. 8-year-old
D. 8 year old
答案:
A. 8-years-old
B. 8 years old
(答案→)C. 8-year-old
D. 8 year old
解析:句意:那个8岁的男孩正在和他的祖父下象棋。这里空格后有名词,所以这里需用的是复合形容词作定语。其结构是数词—名词的单数—形容词。8 years old不能作定语。故选C。