Question

Between the two parts of the concert is an interval, ____ the audience can buy ice-cream.

Between the two parts of the concert is an interval, ____ the audience can buy
ice-cream.A.when B.where C.that D.which
答案A

我选D 我认为是非限制性定于从句。。。。怎么区别开

请解析

Answer 1

逗号后面的确是非限制性定语从句，但是正确答案选A，而不是D。

楼主可能搞不清关系代词和关系副词的区别吧。
该定语从句所修饰的先行词是an interval，将其放入该非限制性定语从句中，它不能单独充当主语/宾语/表语/定语等成分（这恰恰就是关系代词which等在定语从句中的功能）。
从句明显缺少的是一个during which这样时间状语，而关系副词when = 介词（during）+ 关系代词（which）= 介词（during）+ 先行词（an interval）。
即定语从句可以变化为：
(when) the audience can buy ice-cream
= (during which) the audience can buy ice-cream
= (during an interval) the audience can buy ice-cream
= the audience can buy ice-cream (during an interval)
听众可以在幕间休息期间购买冰淇淋