一道TPO8的阅读题，求助。

fly0022UID: 3002615

原文
These calculations suggest that a period of about one million years would have been required. However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million years. So the unusually high concentration of lr seems to require a special explanation.

10. Paragraph 5 implies that a special explanation of lr in the boundary clay is needed because
○the lr in microscopic meteorites reaching Earth during the Cretaceous period would have been incorporated into Earth’s core
○the lr in the boundary clay was deposited much more than a million years ago
○the concentration of lr in the boundary clay is higher than in microscopic meteorites
○the amount of lr in the boundary clay is too great to have come from microscopic meteorites during the time the boundary clay was deposited


问题：However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million years这话意思是“ 然而，其他可靠的证据表明分界的粘土量不需要100万年的积累”？ D选项说分界的泥土层太大而不能是来自小陨星的撞击的时候？  
意思不是矛盾么？

fly0022UID: 3002615

顶下帖子。 来个好心人帮帮忙啊 。。

fly0022UID: 3002615

还是没人。。再顶！！

zyc415UID: 2636022

1 那个ir 浓度很高的clay需要小星星不断撞击形成
2 科学家算出来，要撞100万年才能形成文中所述的ir 的clay
3 然而又有证据证明，那个clay的形成并没有经历100万年
4 所以需要新的解释（小星星不断撞，撞了100万年这个解释是不对的）
所以选D啦

fly0022UID: 3002615

4# zyc415
终于有个鸟我了。。热泪盈眶、。。
不对吧？撞100万年？ 是粘土需要积累100万年吧。。他说那个粘土沉淀不需要100万年的积累？时间越久，越厚的吧？选项里是太厚而不可能是小行星撞击？我觉得应该是太薄而不能吧？
求解释

zyc415UID: 2636022

需要联系这一段前面几句话来看啦~只看这两句信息不完整~

zyc415UID: 2636022

而且，选项并没说“厚”~说的是ir的amount太大~

fly0022UID: 3002615

6# zyc415
原文：
It has not been common at Earth’s since the very beginning of the planet’s history. Because it usually exists in a metallic state, it was preferentially incorporated in Earth’s core as the planet cooled and consolidated. lr is found in high concentrations in some meteorites, in which the solar system’s original chemical composition is preserved. Even today, microscopic meteorites continually bombard Earth, falling on both land and sea. By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of lr in the boundary clay. These calculations suggest that a period of about one million years would have been required. However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million years. So the unusually high concentration of lr seems to require a special explanation.
In view of these facts, scientists hypothesized that a single large asteroid, about 10 to 15 kilometers across, collided with Earth, and the resulting fallout created the boundary clay. Their calculations show that the impact kicked up a dust cloud that cut off sunlight for several months, inhibiting photosynthesis in plants; decreased surface temperatures on continents to below freezing; caused extreme episodes of acid rain; and significantly raised long-term global temperatures through the greenhouse effect. This disruption of food chain and climate would have eradicated the dinosaurs and other organisms in less than fifty years.

fly0022UID: 3002615

7# zyc415
那就用  “少”吧？  反正 一样的。

zyc415UID: 2636022

楼主，我发现您对however后那句话的理解和我不一样，我的理解就是4楼的第3点啦~

zyc415UID: 2636022

By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of lr in the boundary clay.
土层里有多少ir，是一段时期内小星星的数量 乘以 时间 决定的
现在的事实是，土层里的ir量很大，并且，时间不够长
因此，小星星这个理论不对，因为它无法解释，为什么土层里的ir量那么大

fly0022UID: 3002615

焦点还是对 However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million years 这句的理解？
文勇的翻译是 “这种计算表明形成这种沉积可能需要一百万年。然而其他可靠的证据则表明沉积这层粘土可能不需要一百万年。”

zyc415UID: 2636022

这个翻译也是可以帮助读者选出D选项的~
如果依据小星星理论，形成这种沉积要100万年；
但是可靠证据证明，这种沉积不需要100万年；
因此，小星星理论不对（靠小星星，不可能在短于100万年的时间内形成这样的土层）

fly0022UID: 3002615

13# zyc415
题目是可以做的出的。
但是我还觉得不对。
不过算了。
感谢您啊。。