and/or 连接的两个同类名词 前面都需要加冠词 还是只需要第一个前面加冠词?

冠词的重复
①两个名词表示两个不同的人或事物,二者前均需加冠词.
A teacher and a student entered together.
Tom has bought an English dictionary and a French dictionary.
②用both… and…所连接的两个名词前均需加冠词.
Both the boys and the girls did well in their exam.
③虽然有些名词常成对出现指同一个人或事物,但要强调每一个对象或想分别给以清晰的概念时,可重复使用冠词.
I bought a watch and a chain.
He has a father and a mother.
She is a doctor and a nurse.
The husband and the wife were discussing the education of their son.