____________,he talks a lot about his favorite singers after class. A.A quiet student as he may be B.Quiet student as he may be C.Be a quiet student as he may D.Quiet as he may be a student 这是一道今年高考题 答案是B 但是我也见过语法书中描写A的形式 这到底是怎么回事那 请高人指点 

AS或者THOUGH出现部分倒装,省略冠词

就是相当于though(as) he may be a quiet studennt.