She/He is a English teather(使用冠词:a)The teacher is from English.(使用冠词：the)
ATeacher Who is from/in English(语法,用who引导的定语从句,冠词 a)
这样的句子很多,但类型大都相同,冠词就有'a'' the'' 了,o(∩_∩)o !