请教GWD25-Q24 ^ ^

wadsoda

Although improved efficiency in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

          A.in converting harvested trees into wood products may reduce harvestrates, it will stimulate demand by increasing supply and lowering prices, thereby boosting

         B.in converting harvested trees into wood products may reduce harvestrates, demand will be stimulated because of increasing supply andlowering prices, which boost

         C.of converting harvested trees into wood products may reduce harvest rates, it will stimulate demand by increasing supply and lowering prices,which boosts

         D.of harvested trees being converted into wood products may reduceharvest rates, it will stimulate demand, because it will increase supplyand lower prices, thereby boosting

         E.when harvested trees are converted into wood products may reduce harvest rates, demand will be stimulated because of increasing supplyand lowering prices, which boost、

A 和 B纠结~  最后选了A。 觉得B中的which有指代不清的嫌疑。大家来帮忙解答一下吧！
多谢啦！

zcooles

这个题我选A.
首先A,B的语法都没错，那么就从逻辑入手。
其一：
A里面用了by increasing supply and lowering price明确指出了动作发出者是improved efficiency。而B里面用了because of increasing supply and lowering price，使得我们并不知道increasing supply and lowering price是不是improved efficiency造成的，而且还会以为是刚好business cycle到了一个mature的阶段，供应上升、价格下降。
这么说吧，B翻译过来是：虽然提高的制木效率可能会降低收成率，但是需求还是会被刺激因为供应上升、价格下降，供应上升、价格下降是可以促进消费的。 -->  没有了原句明确表达的：供应上升、价格下降是因为improved efficiency引起的明确含义。

其二：
demand是需求，consumption是消费。需求增加是消费增加的直接原因，而increasing supply and lowering price并不是消费增加的直接原因，所以B里面which指代了increasing supply and lowering price是错误的，increasing supply and lowering price并不能boost consumption，他们只能通过刺激需求来boost consumption. A里面用boosting很好地反映了这一点。 |||||||||||||||||  另外，也可以发现，B里面割离了demand和consumption的关系，两者其实是有因果关系的，但是在B里面变成了两个独立个体，变得没有关系（其实这是本句which最大的错误所在）。

其三：
B中because of increasing supply and lowering prices中increasing和lowering并不是gerund，而是现在分词做adj.，因为如果是gerund，还是有一个问题：increasing和lowering没有动作发出者是谁 --》 gerund的动作发出者必须明确，如A中by increasing supply and lowering prices中increasing和lowering的动作发出者是it，即improved efficiency。所以B里面的increasing和lowering是现在分词做adj.，问题又出现了：GMAT里面表达“上升的”、“下降的”一般都是用rising和declining，这样没有歧义，不会让读者在读句子的时候疑惑这个doing究竟是gerund还是present participle。所以B里面这两个词的用法虽然不能判错，但一定是用得不好的。

其他：
至于以前争议贴中讨论which是否有指代歧义、B的被动是否不好，都不是判错原则。

附上demand和consumption的区别：
traceback: http://www.stonybrook.edu/sustai ... /facts/demand.shtml
When speaking about electrical energy, there are two related, yet different, measurement parameters that need to be understood: consumption and demand.
   Consumption is a more familiar concept for most people. Simply put, it is the total amount of energy used. Demand is the immediate rate of that consumption.
   A simple analogy is a pile of rocks of various sizes and weights. Let's say that you were moving the pile. The total weight of the rocks is similar to the consumption because it represents the total energy you would expend. The weight of the largest rock is similar to the demand because it represents how much power you would need to have "available" to move that one rock at that instant in time.
   Mathematically, energy consumed is represented by kilowatt hours (kWh). These are what the electric meter records as the dials turn. The rate of consumption would be kilowatt hours per hour or just kilowatts (kW). Typically electric demand is not measured for residential customers. However, commercial customers are charged for both the energy used and how fast they use it. The faster the collective customer base uses energy the more the utility must be able to supply.
   How much energy the system must be able to generate to meet the instantaneous load (even if it's only for a short duration) is called its capacity. This concept is also used when designing a system or building so that electrical distribution equipment is properly sized. The capacity of a utility must be able to meet the demand so no customers are deprived of their electricity.
   Everyone probably knows somebody who can't turn on their toaster and microwave at the same time without blowing a fuse. This example demonstrates a circuit that does not have the capacity to meet the demand. However, if these devices are operated one after the other, the energy would be readily available.

wadsoda

哦~LZ的解释很精辟！
启发了我不要单单从语法上来考虑，而应该看得更深入一些！！
真是太感谢了！ 希望自己杀鸡成功！