Jenny's shoes were worn out,she wanted to buy a new[ ] shoe shoes one pair参考答案是pair,但老师说一个名词地二次出现时可用one来代替,求解答用pair不用one的原因,详解,

Jenny's shoes were worn out,she wanted to buy a new[ ] shoe shoes one pair参考答案是pair,但老师说一个名词地二次出现时可用one来代替,求解答用pair不用one的原因,详解,
Jenny's shoes were worn out,she wanted to buy a new[ ] shoe shoes one pair
参考答案是pair,但老师说一个名词地二次出现时可用one来代替,求解答用pair不用one的原因,详解,

Jenny's shoes were worn out,she wanted to buy a new[ ] shoe shoes one pair参考答案是pair,但老师说一个名词地二次出现时可用one来代替,求解答用pair不用one的原因,详解,
首先前面没有出现pair,后面不能用one代替pair,
另外鞋子是一对的,所以用pair,不用one（单数）