请教GWD1-Q14

onion76

只说当时怎么不选A的：productivity 的double比较只存在于两个时间点，即五年前和五年后，而A选项的意思是五年之内的总产量double了，这个确实就得不出来了。我们可知当前和五年前那一年比，产量double，但不可知中间的变化曲线啊。之所以选C，是实在没的选，那个Even Though确实有让步的意思。

champeaux

onion76 发表于 2013-2-3 20:16
只说当时怎么不选A的：productivity 的double比较只存在于两个时间点，即五年前和五年后，而A选项的意思是 ...

我当时就是这么想的....可能GMAT没有那么高深，要考虑到时间点和时间段吧.....因为题目是must be true类型，所以觉得C选项比题干给出的信息推出多了那么几步....

sunlight841206

个人觉得此题暗含“整体”与“个体”的概念：
题目中所讲的That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia’s coal industry.  Coal output per miner in Tribnia is double what it was five years ago, even though no new mines have opened.
这里的output per miner 的double好似是个“整个行业平均的概念”

答案中：
B.       Any individual Tribnian coal mine that achieved an increase in overall output in the past five years has also experienced an increase in output per miner.
C.      If any new coal mines had opened in Tribnia in the past five years, then the increase in output per miner would have been even greater than it actually was.
D.      If any individual Tribnian coal mine has not increased its output per miner in the past five years, then that mine’s overall output has declined or remained constant.

B\C\D都是在说“行业中一个个体”，我们不能由“整体平均特性”推出“个体特性”，因为个体有时会是“特例”

光明使者开盖

既然说人数是可以变化的，为什么A对啊

zzloveyibo

我晕。。。看来是我想多了，，，
我当初写认为A不对的原因是虽然总产量理论上市上升了，但是每个矿总是有限制的(可能被开采完)，所以想多了，，，就错了。。。。

ciciwenwen

A. If the number of miners working in Tribnian coal mines has remained constant in the past five years, Tribnia's total coal production has doubled in that period of time.(对，因为人数不变，但人均效率翻倍，所以，人均产量及总产量均翻倍)
B. Any individual Tribnian coal mine that achieved an increase in overall output in the past five years has also experienced an increase in output per miner.（不一定，如果单个矿产量提升了，有可能是人均产量没提升，但是矿工数量提升所致）
C. If any new coal mines had opened in Tribnia in the past five years, then the increase in output per miner would have been even greater than it actually was.（不一定，若有新矿产量，则总体矿产量的确提升，但是若矿工人数变多，则人均不一定多，有可能更少）
D. If any individual Tribnian coal mine has not increased its output per miner in the past five years, then that mine's overall output has declined or remained constant.（不一定，人均产量没变化，但是若矿工增加了，则总产量提升，而非降低或不变）
E. In Tribnia the cost of producing a given quantity of coal has declined over the past five years.（无法推出）
所以，这道题，在A中就暗示了，必须考虑矿工人数的变化情况，GMAT算是仁慈了。我觉得是。。

Serena0304

ciciwenwen 发表于 2014-4-1 22:32
A. If the number of miners working in Tribnian coal mines has remained constant in the past five yea ...

赞一个！

vickizhq

onion76 发表于 2013-2-3 20:16
只说当时怎么不选A的：productivity 的double比较只存在于两个时间点，即五年前和五年后，而A选项的意思是 ...

我也是这么想的，第一时间就排除a了。。。。

Raycyn

ciciwenwen 发表于 2014-4-1 22:32
A. If the number of miners working in Tribnian coal mines has remained constant in the past five yea ...

这种题目的人均产量提升是由于技术的应用难道不是大前提么？？？
就是题干中的意思就是在T这个地方这个技术已经应用了，已经提高了产值
所以，我就感觉莫名其妙无法推断了。

锅巴要加油

shallowshade 发表于 2011-4-14 22:47
觉得这里的重点应该是一个公式：总产量=个人单位产量*人数（矿工数）；A想就是这么对的；B项是总量增，单产 ...

同意！