The days ______ you could travel without a passport are a thing of the past.

题目

The days ______ you could travel without a passport are a thing of the past.
A) whenever B) wherever
C) on which D) in which

答案

答案：D
本题考察的是定语从句的用法.AB都不能引导定语从句,我们首先排除.答案C 是on which,即：on the day,很显然是错误的,应该是in the days,in which 相当于when,所以正确答案是D.