这两道GWD题超级想不通，谁来帮我解释下？

Q14:

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

答案是B,虽然我也承认A的前半段不如B来的通顺和简洁，但是后半段大家看尤其是和划线外的内容连接起来读，A是as companies that compete one day may be partners the next.  B是as competing companies one day may be partners the next. B是不是根本就读不通啊。

Q18:

Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.

1. Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.
2. Over the course of the eighteenth century a tripling in the average output of ironwork was due to the replacement of charcoal by coal for the fuel used in the smelting of iron ore, in addition to several improvements in blowing machinery.
3. With charcoal’s being replaced by coal as the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
4. The replacement of charcoal with coal for the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
5. Charcoal being replaced by coal as the fuel used in the smelting of iron ore, and several improvements in blowing machinery, which tripled the average output of ironwork over the course of the eighteenth century.

哪为高手能告诉我为什么D不对吗，答案给出的是C

Q14,

Option A, "the more estabilished industries", 这个结构有歧义，more是修饰established 还是 industries  类似于more beatiful girls, more beatiful or more girls?

companies that complete 我觉得读起来不顺，猜想complete是vi. 通常使用手法是 sb. complete with/against sb.

Q14,

Option B, 最后的分句"as competing companies one day may be partners the next", 考的是parallelism, "competing companies" 对应 "partners", one day 对应 the next

Q 18,

Option D, 前面的分句"The replacement of charcoal with coal for the fuel used in the smelting of iron ore and several improvements in blowing machinery"不完整; replacement with错, 应为replacement by; for the fule, for错