Question

The Liberty Bell, formerly housed in Independence Hall, ________ in Philadelphia, was moved to a separate glass pavilion in 1976．

1. A.
   which a historic building
2. B.
   a historic building which
3. C.
   was a historic building
4. D.
   a historic building

Answer 1

D
句子有完整的主谓宾，空格部分成分是主语的同位语，A、B项从句少谓语；C项后边已经有谓语了，此处又没有从句引导词，was多余。