He is only____11-year-old boy,so he can't do so much work in____hour.

问题描述:

He is only____11-year-old boy,so he can't do so much work in____hour.
A.an ; a B.an ;an C.a;an D.a;a ,

11(eleven) 和后面的 hour 都是元音开头,所以用 an