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.

老师我还是想借着这道题问您论证方法，课上您说必须高度概括且逻辑严密，那我在描述树的数量和报纸供给的问题的时候，我可不可以说：文章没有adress树的数量是否能持续供给足够的纸张，因为没有support说明树的数量是否足够能为当年提供5m份的报纸，如果可以…是否为未来继续提供

请问王文静老师 有两个问题1，上课您说因为是修饰need动词的所以不能在名词间做比较。那是不是可以理解为如果是比较修饰动词的就不能省略句子成分？2，b和e选项中的it很奇怪 这个有语法错误吗？这种从句中再提到主语可以直接用代词吗？还是得用that？

求教金老师～

老师我想问一下newspaper这道题，我的逻辑提取是：作者认为这家报社有自己的树 从而 可以保持供应新的报纸，所以回收旧报纸这个事是不必要的。我找的问题是forests的数量是否有可以消耗5m，如果有是否能够能够保证树的数量每年甚至每天提供报纸。此外我找不出其他问题了。

How many 3-letter codes can be formed by choosing, without replacement, 3 letters from the word “Banana”?想请问陆旭老师这道题用box method怎么解？

20og 741题，答案是A选项，想问一下B选项。希望张慧雯老师解答一下 我的理解在图二（字太多了140字放不下）

为什么不能选b选项呢？感觉b的结构更好一些而且后面加上he也没有问题：有七本书-4本文章和三本诗歌

请徐老师讲解一下这道题，谢谢！我算不出来选项里有的数不知道式子哪里列错了

我这道题n和k代了两个数进去但算出来五个选项没一个是和题目里的式子相等的……求教老师！谢谢！

老师这道题难道不是100减去2的倍数49个，3的倍数33个，再加上6的倍数16个最后得34个吗？求解答！谢谢！