Zhang Yu is a girl from Sichuan.A. twelve years oldB. twelve-year oldC. twelve–years-oldD

问题补充：

Zhang Yu is a girl from Sichuan.

A. twelve years old

B. twelve-year old

C. twelve–years-old

D. twelve-year-old

答案：

A. twelve years old

B. twelve-year old

C. twelve–years-old

(答案→)D. twelve-year-old

解析：此题考查合成形容词的基本构成，根据语境可知张宇是个来自四川的一个12岁的小女孩，故选D。