Question

Is this research center ________ you saw the modern equipment last year?

A. which
B. that
C. the one that
D. the one where

Answer 1

答案D
将疑问句改为陈述句：this research center is…显然缺少先行词，必须加上代词the one来作先行词，又因定语从句不缺主语或宾语，所以用关系副词where。假若在this后加the，就选where，请想想这是为什么。