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。

调查1200人对A B C 的喜好，喜欢A的40%，喜欢B的58%，喜欢C的40%，同时喜欢AB的30%，求喜欢C但不喜欢A B的人

问题：在“数的整除性质小节中”，第一段写到，如果a能被b整除，记作aΙb. 但如果照这么理解的话，为什么在性质3: 如果b、c都能整除a且b和c互质，那么b与c的积能整除a。以上说法化成公式的表示为：bΙa 。但如果根据上面的被整除表达，这里不应该写为aΙb嘛？

G（x）表示x的取整且是小于x的，L（x）表示x取整且是大于x的，问L（x）-G（x）的所有可能值的的集合？ （-1,0） （1,0）等

题目：1993年的元旦是星期五，1994年的元旦是星期几。 问题：在文字解释中提到，问题的实质是求用7去除某一天的天数后所得的余数。然后引出，因为15与365除以7后，余数都是1，所以15与365对于模7同余。但15这个数字是怎么推到出来的呢？

问题：由于以前完全没有学习过“同余”的概念，因此书中的解释完全不明白。还烦请MAY老师帮忙讲解一下。

题目：求143∧89（143的89次方）除以7的余数 问题：（1）如何利用同余的概念推出最后的结果的？ （2） 如果可以不用同余概念，还有什么其他方法可以处理此类题型嘛？

题目：A Printer numbered consecutively the pages of a book, beginning with 1 on the first page. In numbering the pages, he printed a total of 189 digits. How many pages are there in the book? 问题：看了中文翻译并听了管老师的讲解，我都没弄明白这个题目的解题思路。的别是对“a total of 189 digits”的处理。

DS：已知半径为7，求ABR 的周长？ 条件1：∠x=120 度 条件2：△ABR 的面积为(49/9) π 图片附件

题目：If n is a prime number greater than 3, what is the remainder when n的平方is divided by 12? 问题：当管老师解题时，他出了3个方程式，分别是： 1） n=3A+1, n的平方=9A(square)+6A+1 2) n=3A+2, n的平方=9A(square)+12A+4 3) n=2A+1, n的平方=4A(square)+4A+1 我不明白的点是：这3个方程式是怎么推到或者是一看到题目就这么设出来的？

有图。