标题: OG13-CR-59对于正确选项的疑惑 [打印本页] 作者: MichaelRen 时间: 2015-7-14 22:15 标题: OG13-CR-59对于正确选项的疑惑 When there is less rainfall than normal, the water level of Australian rivers falls and the rivers fl ow 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 fl ow has been controlled by damming than in rivers that fl ow freely.
原文指出algae在slow-moving环境下生长的更多,原文最后要让我们解释的是为什么“algae levels are low even in very slow-moving river water”,这一句话明确指明了题目的考虑范围是在有water(水流)的情况下吧,D选项都干成dry up了,都没water了,不在题干的考虑的前提范畴下吧。虽然其他选项也都有问题,但我觉得这个正确选项也挺奇怪,我很快就排除掉的了。跪求大神帮忙解答一下!感激不尽!作者: 我从没去过纽约 时间: 2015-7-14 23:07
The correct answer is C?作者: MichaelRen 时间: 2015-7-15 13:58
我从没去过纽约 发表于 2015-7-14 23:07
The correct answer is C?
D is the correct answer.作者: 我从没去过纽约 时间: 2015-7-16 04:44
没有水了还怎么活。。完全改变了生存环境啊。。生存环境没有了 自然就减少数量了作者: alzn2765 时间: 2015-8-6 11:02
你这么理解就是完美的跳到出题者给你挖的坑里。