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.

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求问此题的解题思路：已知整数0到k的乘积能被735整除。 问：k的最小值是多少？

请教一下may老师第26题

请教一下may老师第8题

请教一下may老师23题

求问此题的解题方法：符合k，k+2，k+4三个数都是质数的set有多少个？（k>1) 答案有：0, 1，2，3，>3。请问May老师这种题型该怎么求解呀？谢谢！

从阴影中任取一点，问y小于x的概率是多少？

想问一个数学题，有一组数，问能否确定range？ 1. mean is given 2. standard deviation is given

7/15寂静：所有员工都大于20岁. Of the 2000 employees, is the avg age at least 35? 1. 50% 员工是大于40岁 2. 25% 员工是大于65岁 这道题网上有C和E两种争论；我所不明白的点是：条件2中的25%是否包含在条件1的里面；我觉得答案应该是C。因为：35*2000=70000岁；（1）+（2）可得41*500+66*500+21*1000=74500＞70000.不知道我的思路是否正确。谢谢老师的答疑！

【请May老师回答】这题鸡精提供的答案是D 可是我觉得第二个条件不能得出呢 假设n三次方是x平方 除以n平方 是可以得到x/ n 平方 但是x/n 不一定是整数呀？