According to a theory advanced by researcher Paul Martin，the wave of species extinctions that occurred in North America about 11,000 years ago，at the end of the Pleistocene era，can be directly attributed to the arrival of humans，i.e.，the Paleoindians， who were ancestors of modern Native Americans. However，anthropologist Shepard Krech points out that large animal species vanished even in areas where there is no evidence to demonstrate that Paleoindians hunted them.Nor were extinctions confined to large animals： small animals，plants，and insects disappeared，presumably not all through human consumption. Krech also contradicts Martin's exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene. Still，Krech attributes secondary if not primary responsibility for the extinctions to the Paleoindians，arguing that humans have produced local extinctions elsewhere.But，according to historian Richard White，even the attribution of secondary responsibility may not be supported by the evidence. White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species，and Krech，though aware that the dates are controversial，does not challenge them；yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago. 　3. In the last sentence of the passage， the author refers to “recent archaeological discoveries” (lines 27-30) most probably in order to 　　(A) Refute White's suggestion that neither Martin nor Krech adequately account for Paleoindians' contributions to the Pleistocene extinctions 　　(B) Cast doubt on the possibility that a more definitive theory regarding the causes of the Pleistocene extinctions may be forthcoming 　　(C) Suggest that Martin's， Krech's， and White's theories regarding the Pleistocene extinctions are all open to question 　　(D) Call attention to the most controversial aspect of all the current theories regarding the Pleistocene extinctions 　　(E) Provide support for White's questioning of both Martin's and Krech's positions regarding the role of Paleoindians in the Pleistocene extinctions 老师，我在做这道题的时候，首先定位到最后一句觉得没说什么重点，就有个yet转折，可能这是用来驳斥前面的某些观点的。所以看选项找有没有驳斥的意思的， 发现5个选项全都在驳斥。。。心里慌了往前找。再回去找的时候时间已到。我就随便选了个B（时间一到各种混乱），因为在做这篇文章之前，我大体看了下原文，记住了原文讲的是P反驳M，W反驳P。后来答案我也看明白了，我认为我做这道题的思路出现了偏差，我想问一下应该怎么修正。

老师我还是想借着这道题问您论证方法，课上您说必须高度概括且逻辑严密，那我在描述树的数量和报纸供给的问题的时候，我可不可以说：文章没有adress树的数量是否能持续供给足够的纸张，因为没有support说明树的数量是否足够能为当年提供5m份的报纸，如果可以…是否为未来继续提供

请问王文静老师 有两个问题1，上课您说因为是修饰need动词的所以不能在名词间做比较。那是不是可以理解为如果是比较修饰动词的就不能省略句子成分？2，b和e选项中的it很奇怪 这个有语法错误吗？这种从句中再提到主语可以直接用代词吗？还是得用that？

求教金老师～

老师我想问一下newspaper这道题，我的逻辑提取是：作者认为这家报社有自己的树 从而 可以保持供应新的报纸，所以回收旧报纸这个事是不必要的。我找的问题是forests的数量是否有可以消耗5m，如果有是否能够能够保证树的数量每年甚至每天提供报纸。此外我找不出其他问题了。

How many 3-letter codes can be formed by choosing, without replacement, 3 letters from the word “Banana”?想请问陆旭老师这道题用box method怎么解？

20og 741题，答案是A选项，想问一下B选项。希望张慧雯老师解答一下 我的理解在图二（字太多了140字放不下）

为什么不能选b选项呢？感觉b的结构更好一些而且后面加上he也没有问题：有七本书-4本文章和三本诗歌

请徐老师讲解一下这道题，谢谢！我算不出来选项里有的数不知道式子哪里列错了

我这道题n和k代了两个数进去但算出来五个选项没一个是和题目里的式子相等的……求教老师！谢谢！

老师这道题难道不是100减去2的倍数49个，3的倍数33个，再加上6的倍数16个最后得34个吗？求解答！谢谢！