求助！！OG16 CR78题还请大神说一下解题思路!!

ZRannie · 发表于 2016-9-17 04:43:20

78. When there is less rainfall than normal, the water level of Australian rivers falls
and the rivers flow more slowly. Because algae whose habitat is river water grow
best in slow-moving water, the amount of algae per unit of water generally
increases when there has been little rain. By contrast, however, following a period
of extreme drought, algae levels are low even in very slow-moving river water.
Which of the following, if true, does most to explain the contrast described above?
(A) During periods of extreme drought, the populations of some of the
species that feed on algae tend to fall.
(B) The more slowly water moves, the more conducive its temperature is to
the growth of algae.
(C) When algae populations reach very high levels, conditions within the
river can become toxic for some of the other species that normally live
there.
(D) Australian rivers dry up completely for short intervals in periods of
extreme drought.
(E) Except during periods of extreme drought, algae levels tend to be higher
in rivers in which the flow has been controlled by damming than in rivers
that flow freely.

望大神可以回复！蟹蟹~

VincentFSJ · 发表于 2016-9-17 09:19:34

你看extreme嘛，把conclusion读五遍就知道在问什么了

Fiona09 · 发表于 2016-9-18 16:25:22

文章是说藻类在水较少的时候，比正常水量时，要生长得好，这是因为slow-moving water。但在干旱时，藻类却比slow-moving water时还要少，

问什么能解释这一对比？其实是问原因

A项——吃藻类的动物的数量开始下降（1. 文中并没有提到这个；2. 吃藻类的动物少了，藻类的数量就应该是增加的，而这与原文的结论相背。）
B项——温度成为影响藻类生长的另外一个原因（文只是说有没水，但并没提温度）
C项——当藻类生长量最高时会抑制其他藻类生长（原文没想从数量上进行比较吧只是从水量比较）
D项——说干旱时没水了（和文中讨论的水量有关，且我们知道极度干旱时，一点水都没有，藻类肯定长得不好。）
E项——比较对象有些问题，文中没说有大坝的和水流自由的河中进行对比

ZRannie · 发表于 2016-9-20 10:18:28

Fiona09 发表于 2016-9-18 16:25
文章是说藻类在水较少的时候，比正常水量时，要生长得好，这是因为slow-moving water。但在干旱时，藻类却 ...

多谢！！

求助！！OG16 CR78题还请大神说一下解题思路!!

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求助！！OG16 CR78题 还请大神说一下解题思路!!

所属分类: GMAT考试

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求助！！OG16 CR78题还请大神说一下解题思路!!