og 2015 cr 86题，正确答案中为什么要用进行时而不是完成时

sandrababy

In 2000, a mere two dozen products accounted for half the increase in spending on prescription drugs, a phenomenon that is explained not just because of more expensive drugs but bv the fact that doctors are writing many more prescriptions for higher-cost drugs. (A) a phenomenon that is explained not just because of more expensive drugs but by the fact that doctors are writing (B) a phenomenon that is explained not just by the fact that drugs are becoming more expensive but also by the fact that doctors are writing (C) a phenomenon occurring not just because of drugs that are becoming more expensive but because of doctors having also written (D) which occurred not just because drugs are becoming more expensive but doctors are also writing (E) which occurred not just because of more expensive drugs but because doctors have also written

想咨询一下，文章中的b选项中标红的are becoming和are writing 为什么要用现在进行时呢？  为什么不是完成时或者是一般过去时？ 谢谢！

sandrababy

  求解答啊 想了好久也找了好多资料都不得其解

bombx7

是sc不是cr，楼主太激动了吧。

sandrababy

bombx7 发表于 2015-6-13 00:03
是sc不是cr，楼主太激动了吧。

已经被虐的神智不清了哈哈 我要怎么修改啊tat

bombx7

你为什么要用现在完成时呢，其实这个问题你不用考虑，根据题干找答案就行。至于答案怎么设置，根本不用考虑啊，能选出来就是王道。

sandrababy

sandrababy 发表于 2015-6-13 00:05
已经被虐的神智不清了哈哈 我要怎么修改啊tat

虽然我是做对了，但是还是想了解其中的语法点。怕下次考试考到这个不理解。  这个不是应该是发生在过去的吗  为什么要用现在时呢？

sandrababy

bombx7 发表于 2015-6-13 00:11
你为什么要用现在完成时呢，其实这个问题你不用考虑，根据题干找答案就行。至于答案怎么设置，根本不用考虑 ...

虽然我是做对了，但是还是想了解其中的语法点。怕下次考试考到这个不理解。  这个不是应该是发生在过去的吗  为什么要用现在时呢？

sandrababy

没人理我

lululuna

“if the sentence is meant to emphasize that the action is actually ongoing IN the present timeframe, then the present perfect is not the correct tense to use -- the present perfect (despite its name) does not necessarily indicate that the action continues through the present timeframe.

this is, in fact, the only main function of the present progressive (is/are -ING) tense, which is therefore an excellent choice for this sentence.”

以上是在别的帖子看到的；

说说自己的拙见：
a phenomenon that is explained not just by the fact that drugs are becoming more expensive but also by the fact that doctors are writing

前面用了is，一般现在时，那么在is explained 这个动作发生的timeframe下， 原因应该用现在进行时更好。
我觉得GMAT时态超难的，不能生搬硬套，要靠语义和语境去判断。

hzariel

求问逗号后边在句子中做什么成分啊，逗号前边主谓宾都有了，后边的半句也不是drugs的修饰语，那是什么啊啊啊~~~~我一上来就把A,B,C都排除了5555555