GWD-26-20

chachacha007

这样用they没问题，
这种generalization是可以接受的

开心的柠檬

关于B中的过去完成时，我理解为，因为这里有by 1997,这个时状很重要，说话者站在现在，说，在1997年以前blablabla…，因此是过去的过去，用过完时。注意：这里用的是分号，不是逗号，分号前后是独立的两个句子。

candice1112

A：they的指代没有问题！they本身就是多指代主语，问题在于by
"performed well" 和 "by 2010" 不能够连用。
"By (date)" 是用来表示成就（achievements） or （changes）的变化状态的
E.g.,
* graduating from school (once you graduate, you have a degree; before, you didn't)
* X grows bigger than Y (now it's bigger; before, it was smaller)
* meeting a performance requirement
* performing well enough to qualify for the Olympic Trials]
所以B选项： "figure grow to nearly six hours a week" 才能够表达本质变化，和by 1997连用make sense!

B：如果是要对比 过去的 statistic和现在的，表示现在的可以用现在完成时：
at the start of the 1991 track season, the world record in the men's long jump had stood for 23 years.
（可以发现原句中的in 1981这个时间点概念一点用都没有！其实前一句话就是想体现一个time maker的）
C：这里的whereas是一个 平行的indicator，但是这句话没有平行
D：问题在a figure of nearly six hours
D的错误：
In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores, compared with a figure of nearly six hours 【wordy】 a week in 1997（错！）

In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores, compared with nearly six hours a week in 1997（正确）

由于 figure= 确切的数字，所以，D选项中的a figure of nearly 6 h 就非常的wordy！

E.g., In 1990 the population of Las Vegas was only about 400,000, but by 2010 that figure had grown to 1,200,000.
这里that figure=400,000， 但是不能够替换，因为awkward，

E: in 1997是表达当年所发生的，和正在发生的：growing不match

这是我自己整理的~~大家可以看一下~~

x-tester

大家对A的理解貌似都错了吧。。They指代的是广泛意义的「children in U.S.」（句子如果不是此意，应该就用children who ... in 1981这样的句式），我们平时也这样说，也不见得GMAC的人会在这里作出反人类的诠释。

我觉得Ron大神的解释更靠谱一点：
The meaning of the problem (which is clear to me - and, apparently according to the gmat people, clear to everyone else too) is that the kids were spending that many hours per week by 1997.

if you say "they had spent six hours a week by 1997", all this means is that they had gotten to 6 hrs/wk AT SOME POINT before 1997. it doesn't mean that they're still working that much.

也就是说，在这里过去完成时似乎让句子产生了“在1997年之前他们就已经一星期干6小时”了这样的感觉（即「过去已经完成了」），这个是不正确的，应该是“干活时长慢慢增长，到了1997年已经涨到了6小时一星期”这样才对。

Ron给了另外的例子，给大家参考下：

in 1980 forty percent of East High School class graduated; 67% of the class had graduated by 1997.
--> wrong. this would mean that half of the 1980 class had graduated at any time prior to 1997.

in 1980 forty percent of East High School class graduated; by 1997 the figure had grown to 67%.
--> correct. this would mean that 67% of the '97 class graduated (which is what we mean).

DeliciaAn

顶8楼。

安猪

msuzengli 发表于 2009-6-15 01:25
非NN,欢迎拍砖.In 1981 children in the United States spent an average     &n ...

同意！               

chuck15

x-tester 发表于 2015-5-30 12:26
大家对A的理解貌似都错了吧。。They指代的是广泛意义的「children in U.S.」（句子如果不是此意，应该就用c ...

同意！