Mrs Smith is a head teacher.
或者Mrs Smith is the head teacher of ...(sth)
因为首先mrs smith是一个人,要用单数
其次,the 是定冠词,要表示特定的事物,这里应该用不定冠词a
Mrs Smith is a head teacher.
或者Mrs Smith is the head teacher of ...(sth)
因为首先mrs smith是一个人,要用单数
其次,the 是定冠词,要表示特定的事物,这里应该用不定冠词a