Question

Is this research center( )is full of morden equipment you always mention

Awhere
B.that
C.the one that
D.the one where

Answer 1

C
分析：恢复语序后
this research center is ( )is full of morden equipment you always mentio.
句子中缺少先行词，和关系代词，所以the one做先行词，that 做主语。不能省略
where 不能做主语淘汰D
如果选AB就是表语从句，但是从句中缺少主语，但是AB在表语从句中都不能做主语，所以淘汰AB

Answer 2

C
还原：
This research center is 【the one that 】is full of morden equipment you always mention

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