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.

In the last few years, the number of convicted criminals given community service ( sentences, which allow the criminals to remain unconfined while they perform specific jobs benefiting the public, have ) risen dramatically. Asentences, which allow the criminals to remain unconfined while they perform specific jobs benefiting the public, have Bsentences, performing specific jobs that benefit the public while being allowed to remain unconfined, have Csentences, performing specific jobs beneficial to the public while they are allowed to remain unconfined, have Dsentences which allow them to remain unconfined in their performing of specific jobs beneficial to the public has Esentences allowing them to remain unconfined while performing specific jobs that benefit the public has 答案是E，开始选的D，根据the number判断谓语是单数，只能用has，但是又感觉has是跟着which从句里的，导致整个句子没有谓语。一遍读下来很混乱，不知道想表达什么，也不知道该选什么了。麻烦老师讲解。

Even today, a century after Pasteur developed the first vaccine, rabies almost always kills （its victims unless inoculated） in the earliest stages of the disease. (A) its victims unless inoculated (B) its victims unless they are inoculated (C) its victims unless inoculation is done (D) the victims unless there is an inoculation (E) the victims unless inoculated 答案是B，错选了E。感觉逻辑好混乱，不知道B的its和they指代什么，麻烦老师讲解。

His studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose the concept of an age ( in which great ice sheets had existed in now currently temperate areas. ) A in which great ice sheets had existed in now currently temperate areas B in which great ice sheets existed in what are now temperate areas C when great ice sheets existed where there were areas now temperate D when great ice sheets had existed in current temperate areas E when great ice sheets existed in areas now that are temperate 答案是D，错选了B。BD纠结，不知道该如何判断。第二遍做这道题还是把握不好句意，麻烦老师讲解。

The company is negotiating to sell its profitable credit card ( subsidiary, which it plans to use money from ) to acquire some of the mortgage-servicing operations that are being sold by troubled savings institutions. (A) subsidiary, which it plans to use money from (B) subsidiary, from which it plans to use money (C) subsidiary, and it plans the use of money from that (D) subsidiary and plans to use money from that sale (E) subsidiary and plans the use of money from that sale 答案是D，错选了B。上来就把CDE排除了，因为and前后时态不一致，而且C的it多余。AB比较，which和from which指代的感觉都不是很清晰，然后根据A结尾的from 和原文的to连接起来太别扭，就把A排除了，麻烦老师讲解。

( Based on the growth rates of large modern reptiles such as ) the Galapagos tortoise and examination of fossils of juvenile dinosaurs, scientists estimate that the larger dinosaurs probably lived to be between 100 and 200 years old. A. Based on the growth rates of large modern reptiles such as B. On the basis of growth rates of large modern reptiles such as C. Based on the growth rates of large modern reptiles like D. On the basis of growth rates of large modern reptiles, like those of E. Based on the growth rates as those of large modern reptiles like 答案是B，错选了A。科学家基于爬行动物的生长率，估计了恐龙的存活时间。科学家做based on的逻辑主语有错吗？麻烦老师讲解。 (Based on account of various ancient writers) , scholars have painted a sketchy picture of the activities of an all-female cult that, perhaps as early as the sixth century B.C, worshipped a godness known in Latin as Bona Dea "the good goddess". A. Based on account of various ancient writers B. Basing it on various ancient writer's accounts C. With accounts of various ancient writers used for a basis D. By the accounts of various ancient writers they used E. Using accounts of various ancient writers 答案是E，还是错选了A。做题时在AE纠结了好久，因为不确定学者作为“基于不同作家的解释”的主语是不是错的，而且感觉基于要比使用的表达更好，尽管可以确定using的主语是学者，但还是把E排除了，麻烦老师讲解。 因为不知道这两道题是犯了什么错误，所以去有道查了based on 的例句，发现人是可以做主语的：Based on the finding, one might predict that the bank should increase its display and budget. 以及 Based on that representation, the district judge denied a motion to dismiss the new comlaint. 麻烦老师讲解这几个题的区别。

麻烦老师讲一下

老师，没看懂题目，麻烦讲解一下。

老师，这个题设两个都喜欢的人数＝两个都不喜欢的人数为x，那喜欢a的就是4x,喜欢b的也是4x。总人数就等于x+4x+4x-x吗

老师，麻烦讲解一下。

老师，麻烦讲解一下。