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.

1. as large, integrated companies such as Bethlehem Steel
2. as large, integrated companies, such as Bethlehem Steel, that
3. with large, integrated companies, such as Bethlehem Steel, that
4. while large, integrated companies, such as Bethlehem Steel, that
5. and large, integrated companies such as Bethlehem Steel

Answer: B

I think that here is used in place of which.  A is a run-on sentence.  The industry has changed, as comppanies such as B did something have downsized, or shut down.

后半句我赞同了，这句子是不对。可前半句说 that is used in replace of which，在这情况下，that可以代替which的吗？

请指教