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.

请数学老师讲解 什么叫整数角？没有小数点的不都是整数角吗？我已经忘了勾股定理了 这个题怎么确定？

请数学老师讲解思路，抛物线上的y轴交点为什么是3？一些基础知识我也忘了，请老师一起说下，谢谢。

请数学老师讲解下 这里面的思路我不太明白 第三次落地是不是就加到0.73二次方x 我每次都计算出800

请数学老师讲解 这个条件1我懂。条件2计算量好大。有什么快点的方法

请数学老师讲解思路，根号10我也只能估算出是3.a 感觉计算量好大 短时间完不成

请数学老师讲解下 谢谢

请数学老师解答下思路。为什么截距是2方程就是可以设为y=k(x-2)

请数学老师帮我讲下这类题的思路

还请金老师帮忙解答，谢谢，在讲现在分词的作用时，有两个句子：please answer the question using another way及look at the people lying on thethe beach.不是说现在分词不能做谓语，这两个句子的主谓结构能帮忙分析下吗，谢谢

王文静老师您好，这套题目我不太懂选项B红色字体部分为什么不对，然后released in 2009，这里面的released是动词还是形容词？bringing、winning的造句为什么不对？这道题的考点是哪个？非常感谢