Plankton generally thrive in areas of the ocean with sufficient concentrations of certain nitrogen compounds near the surface where plankton live. Nevertheless, some areas, though rich in these nitrogen compounds, have few plankton. These areas have particularly low concentrations of iron, and oceanographers hypothesize that this shortage of iron prevents plankton from thriving. However, an experimental release of iron compounds into one such area failed to produce a thriving plankton population, even though local iron concentrations increased immediately.

Which of the following, if true, argues most strongly against concluding, on the basis of the information above, that the oceanographers’ hypothesis is false?

A: Not all of the nitrogen compounds that are sometimes found in relatively high concentrations in the oceans are nutrients for plankton.

B: Certain areas of the ocean support an abundance of plankton despite having particularly low concentrations of iron.

C: The release of the iron compounds did not increase the supply of nitrogen compounds in the area.

D: A few days after the iron compounds were released, ocean currents displaced the iron-rich water from the surface.

E: The iron compounds released into the area occur naturally in areas of the ocean where plankton thrive.

答案为Ｄ　分不清DE什么区别啊~  NN帮忙解释一下

海洋学家的假设：没有铁浮游生物活不下去

原文的反对：我放点铁进去浮游生物还是活不下去，因此有了铁浮游生物还是活不下去。

反对原文的反对：放进去的铁都被洋流吹走了。（D）

E说的是放进去的这些铁在浮游生物活得很好的地方自然的出现。说明不了任何问题啊。

偶也没看懂……

C) While the trial was being conducted, production costs at the factory for a similar product, produced without benefit of the new process, also showed a 15 percent reduction

红色部分到底是什么意思呢？是作为分词修饰product吧？可是为什么会有“，”我记得在语法里过去分词短语前面不可以有，吧？如果是谓语，also前面该有个and…………

啊，谁能看懂？谢谢…………鞠躬下……

Plankton generally thrive in areas of the ocean with sufficient concentrations of certain nitrogen compounds near the surface, where plankton live.  Nevertheless, some areas, though rich in these nitrogen compounds, have few plankton.  These areas have particularly low concentrations of iron, and oceanographers hypothesize that this shortage of iron prevents plankton from thriving.  However, an experimental release of iron compounds into one such area failed to produce a thriving plankton population, even though local iron concentrations increased immediately.

Which of the following, if true, argues most strongly against concluding, on the basis of the information above, that the oceanographers’ hypothesis is false?

1. Not all of the nitrogen compounds that are sometimes found in relatively high concentrations in the oceans are nutrients for plankton.
2. Certain areas of the ocean support an abundance of plankton despite having particularly low concentrations of iron.

3. The release of the iron compounds did not increase the supply of nitrogen compounds in the area.

4. A few days after the iron compounds were released, ocean currents displaced the iron-rich water from the surface.

5. The iron compounds released into the area occur naturally in areas of the ocean where plankton thrive.

请注意这道题目是要通过反驳文中的结论来 支持oceanographers的说法：是因为缺少铁导致Plankton不thrive

注意文中的结论是 放入铁没有导致P的增加。

Ａ说不是所有的ＮＣ都对Ｐ有营养。（无关）

Ｂ说有些地方有很多的Ｐ但是铁的含量很低。（这个直接削弱了）

Ｃ说铁的增加不会增加ＮＣ的供给。（无关）

Ｄ说当铁被放了一些天以后，洋流把他们冲走了（所以还是因为没有铁导致没有Ｐ）

E说有P的地方有铁。(这个是否Ｂ退否Ａ的支持其实)

比较D和E，明显D是通过反驳文中的结论来支持O的观点的 所以这里D更好点！