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.

A选项D选项动作发出者分别是什么A为什么不对 这个题能帮忙分析一下吗

请数学老师解答一下 谢谢 答案是星期四十点 我只能算出星期四12点

老师，对于这题ABC的their还有DE的they.他们指代有没有问题呢，就近的话我可以理解成指代records吗The loan company announced it would soon lend money to borrowers with proven records of their not paying back their loans on time,collectively known as subprime lending market. A.of their not paying back their loans on time B.of not paying back their loans on time, a group C.of not paying back their loans on time,with such a group D.that they do not pay back their loans on time. E.that they do not pay back their loans on time,such a group

图片里的并列不是很明白，还得麻烦老师帮忙将一下谢谢，此外， 下面这and连接的并列，不考虑语义，前面是过去分词，后面是it+过去分词这种属于并列吗？brightened the Northern Lights and it possibly knocked

本题是og19、sc720题，答疑器搜不出来，有如下疑问，谢谢老师 ①A选项不太明白， ②so as to 有没有这种说法？ ③D选项的enough和so as to能连用吗 ④E选项的so much as to有这种说法吗

希望金老师回答，这个题D选项有两个because怎么翻译整个句子呢？

老师，我记得所有质数里面只有2一个质数吧？不过答案还是-2，对吧？

张老师您好，这篇文章这道题目我不是很理解。第一句话说some historians认为during世界大战，unions和African A的关系是strong alliance，结束以后就没有了；第二句话说other scholars认为这些unions（organizd labor)一直都在帮助AA，可是并没有提到他们两者在二战之中的关系，所以不太懂为什么选C？老师您能不能说一下您的解题思路以及我思维上的一些问题？谢谢！

老师 这道题目不会做，我不理解为什么有3个男生，3个男生的位置都可以变，所以应该A33*A33，答案是A22，不懂求解

老师，这种题目有重复的字母我经常会有点混淆，我一般用的方法就是6C1*5C2*3C3，就是假设一共有6个空位，字母a选一个位置，还剩5个位置给b选两个位置，请问这种思路对吗？还有答案里的思路，我旁边注释的思路对嘛？求老师指教这类题目好的解题方法，谢谢！