Is this research center _____ you visited the modern equipment last year?

题目

Is this research center _____ you visited the modern equipment last year?
A.where B.that C.the one that D.the one where
请问其余三个为什么不可以?

答案

答案应该是C定语从句的考题.将句子变为肯定句就是 this research center is_____ you visited the modern equipment last year.很显然从句少主语所以要补充出来this research center is_the research center____ 为...