*携隐*小教室（继续回答大家的问题）

Mochaccino

谢谢jj的答复，再问一题og逻辑

53. Two decades after the Emerald River Dam was built, none of the eight fish species native to the Emerald River was still reproducing adequately in the river below the dam. Since the dam reduced the annual range of water temperature in the river below the dam from 50 degrees to 6 degrees, scientists have hypothesized that sharply rising water temperatures must be involved in signaling the native species to begin the reproductive cycle.

Which of the following statements, if true, would most strengthen the scientists’ hypothesis?

(A) The native fish species were still able to reproduce only in side streams of the river below the dam where the annual temperature range remains approximately 50 degrees.

(B) Before the dam was built, the Emerald River annually overflowed its banks, creating backwaters that were critical breeding areas for the native species of fish.

(C) The lowest recorded temperature of the Emerald River before the dam was built was 34 degrees, whereas the lowest recorded temperature of the river after the dam was built has been 43 degrees.

(D)Nonnative species of fish, introduced into the Emerald River after the dam was built, have begun competing with the declining native fish species for food and space.

(E) Five of the fish species native to the Emerald River are not native to any other river in North America.

A is the best answer.

For the hypothesis to be tenable it is important that the fish in streams in the Emerald River area that retain a wide temperature difference have not lost their ability to reproduce. Choice A asserts that these fish could still reproduce and is thus the best answer. Choice B undermines the hypothesis by suggesting a completely different hypothesis; choice C tends to support the claim that the temperature variation has lessened but does not show that this is the right explanation; since D relates a development after the native species began to decline, it does not bear on the hypothesis, which concerns the decline’s original cause; and choice E emphasizes the seriousness of the problem but sheds no light on what causes it.

答案没问题，但是我的思路跟og上说的不太一致，og说A是assert fish could still reproduce, have not lost their ability to reproduce，强调ability.而我选A是因为A指出fish在50 degree的环境可以reproduce,强调的是tempreture的条件。我想问下我的思路对吗？和og的思路是不是相差很远啊？怎样才能跟og的思路一致呢？

没找到有讨论稿，所以发到这里请大家看看，麻烦携隐jj再给解答，thanks.

jaredyu

Question 2 – 4:

       While the most abundant and dominant species within a particular ecosystem                 1

is often crucial in perpetuating the ecosystem, a “keystone” species, here defined                   2

as one whose effects are much larger than would be predicted from its appearance,               3

also play a vital role.  But because complex species interactions may be involved,                 4

identifying a keystone species by removing the species and observing changes  in                   5

the ecosystem is problematic.                                                                                                  6

       It might seem that certain traits would clearly define a species as a keystone                   7

species; for example, Pisaster ochraceus is often a keystone predator because it                            8

consumes and suppresses mussel populations, which in the absence of this starfish               9

can be a dominant species.  But such predation on a dominant or potentially dominant           10

species occurs in systems that do as well as in systems that do not have species that                    11

play keystone roles.  Moreover, whereas P. ochraceus occupies an unambiguous                  12

keystone role on wave-exposed rocky headlands, in more wave-sheltered habitats                  13

the impact of P. ochraceus predation is weak or nonexistent, and at certain sites sand                    14

burial is responsible for eliminating mussels.  Keystone status appears to depend on                     15

context, whether of particular geography or of such factors as community diversity                     16

(for example, a reduction in species diversity may thrust more of the remaining species          17

into keystone roles) and length of species interaction (since newly arrived species                  18

in particular may dramatically affect ecosystem).                                                                19

-------------------------------------------------------------------------

Question 2:

The primary purpose of the passage is to

A.      point out some of the differences between dominant and keystone species

B.      emphasize the complexity of the interactions that occur between two particular species

C.      detail the effect of a particular habitat on the role occupied by a certain keystone species

D.     illustrate the importance of community diversity for the perpetuation of an ecosystem

E.      explain some considerations involved in determining whether a species occupies a keystone role

我选E，可是"题目分类-Verbal"上的答案是D。可是文章从始至终都是在讨论identifying a keystone species，并没有讲述D中所提到的importance of community diversity 。D答案对吗？

番茄笑了

以下是引用tania在2005-7-7 12:34:00的发言：

哦——

终于明白了！谢谢携隐jj和番茄mm的帮助！

番茄，还要额外再感谢你的一个好建议“每天做语法前先看一遍昨天的笔记”，我按照你的方法做，语法的正确率果然比原先有很大提高，思考了一下原因，觉得是看错题笔记有利于提高对自己较弱语法点的熟悉度和敏感度。

我想总结的道理应该也是这样的，不断的总结，不断的熟悉，最后在考试前过一遍自己的总结，有利于在很短时间内迅速重新熟悉一遍所有的语法点，才能在考场保持对所有语法点的敏感性。

再次谢谢番茄！

嗬嗬。。。。真高兴mm有了提高！！我也要努力不然要掉队了~

携隐

以下是引用tania在2005-7-7 17:17:00的发言：

29题和67题略有不同，虽然它们都是weaken。67题要求weaken的是结论，所以正确的weaken选项应是weaken结论的那个选项。67题E选项的错误在于它是原文原因的原因，与结论无关，作者不需要因为E而重新考虑他的观点或做出解释；29题要求weaken的是原因，所以正确的weaken选项应是weaken原因的那个选项，或是提出其他的原因，所以A选项是不正确的，因为A选项既没有weaken原文的原因，也没有提出其他新的原因解释原文结论。

你的理解大体上是对的，做逻辑题首先要看清楚结论是什么，题目要求你削弱的到底是什么。不过，tania，原因属于文章给出的条件，我们是不能去削弱的，我们削弱的对象应该是原因和结果之间的关系。

携隐

以下是引用jaredyu在2005-7-7 18:42:00的发言：


可不可以这么理解: and then (is) only as a way to anticipate higher prices or ensure against shortages. 把as a way当错是插入语.

好像不是插入语哎，因为后面的to anticipate应该是修饰way的。

携隐

以下是引用Mochaccino在2005-7-7 19:47:00的发言：

答案没问题，但是我的思路跟og上说的不太一致，og说A是assert fish could still reproduce, have not lost their ability to reproduce，强调ability.而我选A是因为A指出fish在50 degree的环境可以reproduce,强调的是tempreture的条件。我想问下我的思路对吗？和og的思路是不是相差很远啊？怎样才能跟og的思路一致呢？

没找到有讨论稿，所以发到这里请大家看看，麻烦携隐jj再给解答，thanks.

你的思路没有问题，OG的思路也没有问题。OG的意思是说，要加强是温度的变化导致了鱼的减少，必须保证一个条件，那就是这些鱼的reproduce的能力并没有丧失（排除他因，将减少原因直指向温度）。而A正好说明了鱼的reproduce能力并没有丧失，仍然存在。

cocoabean

以下是引用古镯在2005-7-4 9:32:00的发言：

还有，抱抱COCO，一定要注意身体哦！

呵呵, 恐怕镯子抱不动我了, 昨天体检回来, 我的体重已经飙升到了 125ps, 预计在未来的两个月有望突破150 ps大关, 哈哈, 到时我就是小教室里最重得了吧.

携隐

以下是引用jaredyu在2005-7-8 1:43:00的发言：

Question 2 – 4:

我选E，可是"题目分类-Verbal"上的答案是D。可是文章从始至终都是在讨论identifying a keystone species，并没有讲述D中所提到的importance of community diversity 。D答案对吗？

你是对的，答案应该是E。

gracebin

答案就是E

beibeizhu

原来"好想去旅行"就是传说中的nn携隐jj,我特别喜欢看你的图片,像一个明星在演唱会上的感觉.你真的就是这个样子的吗?