- UID
- 565371
- 在线时间
- 小时
- 注册时间
- 2010-9-13
- 最后登录
- 1970-1-1
- 主题
- 帖子
- 性别
- 保密
|
我也觉得最后一题是选B。。。虽然我觉选C也有选C的理由。。。
但如果看第二段的中心句就会明白1980年的这个事件是用来说明 Large-scale disturbances in one locale also have the potential to alter the genetic structure of populations in neighboring areas 的
然后第三段的结尾,又提到这个影响Such a dramatic increase in straying from damaged areas to more pristine streams results in substantial gene flow, which can in turn lower the overall fitness of subsequent generations.
总之就是说明影响很严重,会导致其他habitat的鱼失去fitness,所以这个题应该是说作者想表明人类对于鱼的影响到了什么样的extent。。。
但是选C呢,Although no one has quantified changes in the rate of straying as a result of the disturbances caused by humans, there is no reason to suspect that the effect would be qualitatively different than what was seen in the aftermath of the Mount Saint Helens eruption
提到了no one has quatified the changes, 但是没有reason去suspect会qualitatively different。。。所以提供一个可以measure impact的方法也是有道理的。。。
所以最后悲剧的纠结在B 和 C了。。。= = |
|