Question

He started walking when he was _____.
A. 2-year-old     B. 2 year old     C. 2 years old

Answer 1

C

试题分析：句意：他在两岁时开始走。2-year-old两岁的，是形容词，一般作定语；2 years old两岁，是一个短语，常作表语。所以选C。