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。

报了617的考试，一战，关于复习计划有一些问题想请教英老师： 1.我考试时间应该是刚刚换库的时候，我平时做GWD数学一般错误不超过5个，这一个多星期数学应该怎样复习？请问是否有必要看前一个月的数学机经，以及怎样有效利用数学机经？ 2.刚刚开始做GWD模考，才做了4天，请问老师能否详细讲讲每次做完模考以后REVIEW的方法，是先把错误的题全部重做，再听答疑，还是每道题都听解释，尽可能吃透，或者是否有其他建议？谢谢！

For the farmer who takes care to keep them cool, （providing them with high-energy feed, and milking them regularly, Holstein cows are producing ） an average of 2,275 gallons of milk each per year. A. providing them with high-energy feed, and milking them regularly, Holstein cows are producing B. providing them with high-energy feed, and milked regularly, the Holstein cow produces C. provided with high-energy feed, and milking them regularly, Holstein cows are producing D. provided with high-energy feed, and milked regularly, the Holstein cow produces E. provided with high-energy feed, and milked regularly, Holstein cows will produce

Heavy commitment by an executive to a course of action, especially if it has worked well in the past, makes it likely to miss signs of incipient trouble or misinterpret them when they do appear. A. Heavy commitment by an executive to a course of action, especially if it has worked well in the past, makes it likely to miss signs of incipient trouble or misinterpret them when they do appear. B. An executive who is heavily committed to a course of action, especially one that worked well in the past, makes missing signs of incipient trouble or misinterpreting ones likely when they do appear. C. An executive who is heavily committed to a course of action is likely to miss or misinterpret signs of incipient trouble when they do appear, especially if it has worked well in the past. D. Executives’ being heavily committed to a course of action, especially if it has worked well in the past, makes them likely to miss signs of incipient trouble or misinterpreting them when they do appear. E. Being heavily committed to a course of action, especially one that has worked well in the past, is likely to make an executive miss signs of incipient trouble or misinterpret them when they do appear.

图发不上来，是一个半圆的隧道然后宽是20 The figure above shows the dimensions of a semicircular cross section of a one-way tunnel. The single traffic lane is 12 feet wide and is equidistant from the sides of the tunnel. If vehicles must clear the top of the tunnel by at least ½ foot when they are inside the traffic lane, what should be the limit on the height of vehicles that are allowed to use the tunnel? A. 5½ ft B. 7½ ft C. 8 ½ ft D. 9½ ft E. 10 ft

Vasquez-Morrell Assurance specializes in insuring manufacturers. Whenever a policyholder makes a claim, a claims adjuster determines the amount that Vasquez-Morrell is obligated to pay. Vasquez-Morrell is cutting its staff of claims adjusters by 15 percent. To ensure that the company’s ability to handle claims promptly is affected as little as possible by the staff cuts, consultants recommend that Vasquez-Morrell lay off those adjusters who now take longest, on average, to complete work on claims assigned to them. Which of the following, if true, most seriously calls into question the consultants’ criterion for selecting the staff to be laid off? (A) If the time that Vasquez-Morrell takes to settle claims increases significantly, it could lose business to other insurers. (B) Supervisors at Vasquez-Morrell tend to assign the most complex claims to the most capable adjusters. (C) At Vasquez-Morrell, no insurance payments are made until a claims adjuster has reached a final determination on the claim. (D) There are no positions at Vasquez-Morrell to which staff currently employed as claims adjusters could be reassigned. (E) The premiums that Vasquez-Morrell currently charges are no higher than those charged for similar coverage by competitors.

麻烦老师,针对我的复习思路,您看看,在复习计划和复习步骤上能做些调整吗? 多谢

若n和p是互不相同的正质数，则在N^4 p^3 和np这几个数哪一个数字恰好有四个正因子？ n^4 有5个 分别是1和4个n p^3 有4个 分别是1和3个p 我觉得np只有3个啊 1 n 和p 我也套用具体数字验证过 但是答案说np也有四个正因子 求老师解答 谢谢！

老师您好， 下面是我格式化的复习计划。 我的思路是先把OG做掉，我现在数学快做完了，然后做阅读，逻辑，语法。 再做模考题。 您给看看有什么需要改进的。 谢谢啦。

请忽略之前发的问题，19考，请赐教4道题

n is an positive integer, 2n=2*4*6*8*(2n-2)*2n, what is the greatest prime factor of (20)+(22)? A 19 B 23 C 29 D 31 E 37 我读不懂这个题 (20)+(22)这是什么意思啊？ 谢谢