老师您好能否帮我讲解下下面这个文章考试时该如何读，我读完这种文章压根不知道在说什么，只知道在讲ocean basin形成机制的几种理论。No very satisfactory account of the mechanism that caused the formation of the ocean basins has yet been given. The traditional view supposes that the upper mantle of the earth behaves as a liquid when it is subjected to small forces for long periods and that differences in temperature under oceans and continents are sufficient to produce convection in the mantle of the earth with rising convection currents under the mid-ocean ridges and sinking currents under the continents. Theoretically, this convection would carry the continental plates along as though they were on a conveyor belt (conveyor belt: n. 传送带) and would provide the forces needed to produce the split that occurs along the ridge. This view may be correct: it has the advantage that the currents are driven by temperature differences that themselves depend on the position of the continents. Such a back-coupling, in which the position of the moving plate has an impact on the forces that move it, could produce complicated and varying motions. On the other hand, the theory is implausible because convection does not normally occur along lines, and it certainly does not occur along lines broken by frequent offsets (an abrupt bend in an object by which one part is turned aside out of line) or changes in direction, as the ridge is. Also it is difficult to see how the theory applies to the plate between the Mid-Atlantic Ridge and the ridge in the Indian Ocean. This plate is growing on both sides, and since there is no intermediate trench, the two ridges must be moving apart. It would be odd if the rising convection currents kept exact pace with them. An alternative theory is that the sinking part of the plate, which is denser than the hotter surrounding mantle, pulls the rest of the plate after it. Again it is difficult to see how this applies to the ridge in the South Atlantic, where neither the African nor the American plate has a sinking part. Another possibility is that the sinking plate cools the neighboring mantle and produces convection currents that move the plates. This last theory is attractive because it gives some hope of explaining the enclosed seas, such as the Sea of Japan. These seas have a typical oceanic floor, except that the floor is overlaid by several kilometers of sediment. Their floors have probably been sinking for long periods. It seems possible that a sinking current of cooled mantle material on the upper side of the plate might be the cause of such deep basins. The enclosed seas are an important feature of the earth’s surface, and seriously require explanation because, in addition to the enclosed seas that are developing at present behind island arcs, there are a number of older ones of possibly similar origin, such as the Gulf of Mexico, the Black Sea, and perhaps the North Sea.

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。