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

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

Is this research center________ you visited the modern equipment last year?

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 Is    this   the  research   center   _____you   visited the lab  last   year  ?

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

. Is    this   the  research   center   _____you   visited the lab  last   year  ?

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

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

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