题干
Daniel started to play_________ piano when he was________ 11-year-old boy.
A：/, a
B：the, a
C：a, a
D：the, an
答案(点此获取答案解析）
D
Daniel started to play_________ piano when he was________ 11-year-old boy.
A：/, a
B：the, a
C：a, a
D：the, an
