A girl became a writer at age of 12, age when many children are still in the primary scho

A girl became a writer at age of 12, age when many children are still in the primary school.
A. an;an
B. the;an
C. an;the
D. the ;the

A. an;an(答案→)B. the;anC. an;theD. the ;the解析：该词考查冠词用法,at the age of……为固定结构，an age when是the age of的同位语，后跟由when引导的定语从句【标签】冠词用法

这下我知道了