问题
选择题
The ________ boy ___________ the fire on May 10th.
A．18 years old, put out
B．18-year-old, put out
C．18 years old, putted out
D．18-year-old, putted out
答案
答案：B
由“数词+名词(+形容词)”构成的这种合成形容词中的名词(year, hour, metre, month等)必须用单数形式，而且只能作定语，而18 years old 只可以做表语；动词put的过去式与原形同形，故选B。