OG 200

200. Certain pesticides can become ineffective if used repeatedly in the same place: one reason is suggested by the finding that there are much larger populations of pesticide-degrading microbes in soils with a relatively long history of pesticide use than in soils that are free of such chemicals.

这题答案就是A,其它我就不赘述了，关于答案的解释我也没有异议，五者相比确实只有A满足条件，但是总觉得有些矮子里拔高子的味道。 想请教的是，整句话是否可以改为：

The finding that there are much larger populations of pesticide-degrading microbes in soils with a relatively long history of pesticide use than in those that are free of such chemicals suggests (or may suggest) that certain pesticides can become ineffective if used repeatedly in the same place.  

黑体是该了以后句子的主体结构，斜体是可不可以用those 替换soils?

这么改了之后，和原句相比有没有岐义？ 假设用这个选项替换A, 即原答案缺席的情况下（ETS永远正确原则）， 这句话有没有可能对？

（钻牛角尖了，但总觉得答案的形式不常用，想用常规点的方式来思考，看看能不能对）

先谢谢各位NN抽空指点。

259. Five fledgling sea eagles left their nests in western Scotland this summer, bringing to 34 the number of wild birds （successfully raised） since transplants from Norway began in 1975.

(A)    bringing

(B)    and brings

(C)   and it brings

(D)   and it brought

(E)     and brought

再加一题，这两题在提问汇总里都没有。关于这题的疑问是题干中为什么不用完成时，是省略用法吗？补全了是不是...birds that have been successfully raised...? 这种省略是否严谨？ 如果不是出现在题干中，而是出现在答案选项中应该算对吗？

还是没有人来回答，也许我考虑得太偏了吧，但万一题目有这样的思路该怎么应对呢？！希望有NN碰巧经过，顺便来看看。

lifelover mm,

其实这两题以前都讨论过，不过由于汇总链接没有及时更新，mm以后可以试着用"搜索“功能查找。但我们会在近期改进工作，由此给你带来的不便，深表歉意！

下面为搜索到的以前的讨论，先请参考。如若还未能解决你的疑问，烦请再顶一下帖子，大家一定会尽量解决你的疑问的。

OG200

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=59466

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=56303

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=39127

OG259
http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=65563

最后，祝你学习快乐！

谢谢LES老大，谨遵教诲，下次一定先查找并且把题目贴全。 不过看了一下讨论，和我的问题还是有些出入，再顶一次，看看有没有其他人有同感或者已经考虑过可以给我释疑的。不过我的问题真的有点偏，因为不是针对答案本身的。

再顶！

你举的这个例子非常好。

我认为，不能用those来指代soils，因为those 是指代那个特定的soils，即soils with a relatively long history of pesticide use 。。。。这样就会有问题了。只能用soils。

如果把你给出的句子中的those改成soils，我想，应该是可以替代A选项的。

为什么要用完成时？你是不是看到V+ed，就以为是have done的结构的省略，其实，还有一种形式哦，be done，被动语态。

借原版主dreadpower的原话来说：用完成时，一定要有充足的理由，或是有时间提示语，或是有明显的意思提示非用不可。

本句就是省略了that are的被动语态，补全了：...birds that  were successfully raised...

谢谢船长，第200题我同意，those替代是会造成歧义（和美国东部地震和西部地震带来的灾害相比较那题类似），但是259题干中的since sth. began in 1975 不可以理解成完成时态的标志吗？“自1975年开始的某个事件”不可以理解为“自1975年”吗？ 比如说： Many NNs have achieved unbelievably high scores in GMAT since the openning of CD forum started in 2000. (i don't know the exact time) ?

偶想商榷商榷。我觉得that, those和it不同，这个特定指代的作用不是那么强烈。比如：

8. Lacking information about energy use, people tend to overestimate the amount of energy used by equipment. such as lights, that are visible and must be turned on and off and underestimate that used by unobtrusive equipment, such as water heaters.

(A)  equipment, such as lights, that are visible and must be turned on and off and underestimate that

(B)   equipment, such as lights, that are visible and must be turned on and off and underestimate it when

(C)  equipment, such as lights, that is visible and must be turned on and off and underestimate it when

(D)  visible equipment, such as lights, that must be turned on and off and underestimate that

(E)   visible equipment, such as lights, that must be turned on and off and underestimate it when

这里正确答案D里最后一个that, 替代的就是energy,但是你不能说这个energy已经被lights用过了，不能再被water heater用了吧?

再比如：

112. Domestic automobile manufacturers have invested millions of dollars into research to develop cars more gasoline-efficient even than presently on the road.

(A)  into research to develop cars more gasoline-efficient even than presently on the road

(B)   into research for developing even more gasoline-efficient cars on the road than at present

(C)  for research for cars to be developed that are more gasoline-efficient even than presently the road

(D)  in research to develop cars even more gasoline-efficient than those at present on the road

(E)   in research for developing cars that are even more gasoline-efficient than presently on the road

正确答案D里的those指的是cars,但是他们明显就是两种car,前面的是还没有造出来的，后面的是已经在路上的。

所以我认为，those的特定指代性不是那么强，而lifelover妹妹说的把soils换成those是可以的。望指教！多谢！