Question

The days__________you could travel without a passport are a thing of the past.

A.in which
B.on which
C.of which
D.at which

Answer 1

【答案】：A
选项中的which引导后边的you could travel without a passport修饰the days，同时，the days表示是一段时间所以which前加介词in构成从句的状语。