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.

请问数学老师 条件2为什么成立 谢谢老师

老师您好，这道阅读理解不会做，用定位的方法读了原文也没太懂为什么选D

文章的最后一句话回答了这个问题，也就是C选项，我不懂为什么正确答案是B

ken老师你好，这道题目我的思路是设97、98、99依次为a、b、c，根据题目得出b=C+y; b=a+x。条件1）x>y，可以得出a<c。 第二个条件不太懂。而且这道题目的开始的的less、 more in 1999，这些术语我转化成公式就浪费了半个小时，想问老师有没有更高效的解决办法？

请数学老师讲解下思路

麻烦老师给我讲解一下这一题，通过The body…was that of the man ，身体是那个男人的一部分，而不是身体是那个男人。这个点排除ABC. DE关于时态部分不是很清晰

请数学老师解答下第三个为什么不行

请数学老师帮我解答下，再讲下怎么画图 谢谢老师

麻烦老师给我辨析一下图1和图2，关于图1那题当时选错之后机构老师给我解答的是40 to 44 million years 是一个时间区间，不能用estimate at 因为 at 有精确到某个点的意味。那么图2的正确答案是不是因为3.47 billion years 是一个精确的年份所以要用 at 。。

麻烦老师给我解答一下这题，这题BUT后面主要想表达的核心语意是 家庭用电少于百分之一和家里面的电仍然是由蜡烛提供。我觉得B 顺着读下去也能表达这个语意，就是 我觉得AB 都能表达这个语意，关于两者的差异我不是很清晰 麻烦老师帮我辨析一下