关于不定冠词a的用法问题
问题描述：
关于不定冠词a的用法问题
一个句子：
Mr.Cassidy,possibly the most popular teacher in our school,serves as advisor for both yearbook and the National Honor Society.
为什么是serves as advisor而不是an advisor?
答
serve as是 vt.用作,充当,担任
从意思上看,advisor 作为一个头衔出现,
所以作为头衔的名词前可以不用不定冠词 "an"