再问TTGWD4-17的E选项，未讨论过

TTGWD4-Q17:

The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel once conducted operations from mining at one end of the process to shipping at the other have greatly downsized, or in some cases shut down altogether.

A.      as large, integrated companies such as Bethlehem Steel

B.      as large, integrated companies, such as Bethlehem Steel, that

C.      with large, integrated companies, such as Bethlehem Steel, that

D.      while large, integrated companies, such as Bethlehem Steel, that

E.       and large, integrated companies such as Bethlehem Steel

the key is B, but why E is wrong?

E中的once 是副词，而不是连词，E中两个动词conducted & have，造成句子run on