Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete one day may be partners the next.

1. Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete
2. Although the lines of competition are clearly defined in industries that are more established, they are blurred and indistinct in the Internet industry, as competing companies
3. The lines of competition are clearly defined in the more established industries, unlike the Internet where they are blurred and indistinct, as companies that compete
4. Unlike more established industries, where the lines of competition are clearly defined, they are burred and indistinct in the Internet industry, as companies that compete
5. Unlike more established industries, with clearly defined lines of competition, those of the Internet industry are blurred and indistinct, as competing companies

这题答案是B,但小妹觉得次题中B,E中最大的问题就是as后面的句式问题，因为这题as后面要说的是companies曾经one day是compete的关系可能next (day)就变成partner的关系了。所以B,E看似用competing companies替代companies that compete，但这并不能表达出来上述我所说的意思来。

所以小妹觉得应该选A，虽然A并不完全符合Palleralism的条件：whereas lines ......, in the internet，但相对于别的选项，小妹觉得还是A好些

...one day may be partners the next.  决定了只能是that compete 结构， 再考虑parallelism, 答案为A.