为什么英语书上是an art teacher而作业本上是a art teacher?

问题描述:

为什么英语书上是an art teacher而作业本上是a art teacher?
书上的原句是:A sclence teacher,an art teacher,and an English teacher.
作业本上是:I have( a)new art teacher,(an)English teacher.
那么究竟哪个是对的?还是说哪个都是对的,

都是对的,元音前面用an,所以是an art teacher,a new art teacher