阅读理解 The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--is almost unbelievable, but several kinds of fish are able to do this. Even more strangely, this curious power has been acquired in different ways by fish belonging to very different families. Perhaps the best known are the electric rays, or torpedoes(电鳐), of which several kinds live in warm seas. They possess on each side of the head, behind the eyes, a large organ consisting of a number of hexagonal shaped cells rather like a honeycomb. The cells are filled with a jelly-like substance, and contain a series of flat electric plates. One side, the negative side, of each plate, is supplied with very fine nerves, connected with a main nerve coming from a special part of the brain. Current passes from the upper, positive side of the organ downwards, to the negative, lower side. Generally it is necessary to touch the fish in two places, completing the circuit, in order to receive a shock. The strength of this shock depends on the size of the fish, but newly born ones only about 5 centime-tres across can be made to light the bulb of a pocket flashlight for a few moments, while a fully grown torpedo gives a shock capable of knocking a man down, and, if suitable wires are connected, will operate a small electric motor for several minutes. Another famous example is the electric eel. This fish gives an even more powerful shock. The system is different from that of the torpedo in that the electric plates run longitudinally(纵向) and are supplied with nerves from the spinal(脊骨) cord. Consequently, the current passes along the fish from head to tail. The electric organs of these fish are really altered muscles and like all muscles are apt (likely) to tire, so they are not able to produce electricity for very long. The power of producing electricity may serve these fish both for defense and attack.

单选题 It can be seen from the passage that______.

【正确答案】 D

【答案解析】本题译文：从本文可以看出，电鳐的发电细胞的形状是六边形。本题要求了解文章主旨的事实和细节。这一题要求我们在对全文整体理解后，并一一对照文中细节，才能做出选择。A认为“产生电的能力是鱼类的一种有别于其他生物的特性”。事实上鱼类中只少数几种特殊的鱼有产生电的能力，并非所有的鱼类。因此A项是不正确的。D认为“电流经过电鳐细胞的正极向上到达负极。”而文中第二段很清楚写有电流从上方的正极向下流到下方的负极，B项是错的。C认为“有些鱼能产生足以开动几台电动机的电量。”而文中对于鱼类所产生的电量的描述最惊人的也只能发动一台小电机。因此B项是不正确的。D项认为“电鳐的发电细胞的形状是六边形。”在文中第二段曾提到电鳐的发电细胞像蜂窝，由日常知识，我们知道蜂窝是六边形的，所以D是正确的。

单选题 Usually you will not get a shock by touching the electric ray in one place only because______.

【正确答案】 C

【答案解析】本题译文：通常你触摸电鳐不会在一个地方感受到电击只是因为你得触摸鱼的两边从而使电路循环完成才会感受到电击。本题要求了解文章的细节。这一题主要是对细节部分的考查。第二段巾的最后一句话详细地写道，“通常需触摸鱼的两边从而使电路循环完成，这样才会感受到电击。”从这里的completing the circuit (完成循环)，我们不难看出 C项是正确的。

单选题 The main idea of the third paragraph is that______.

【正确答案】 B

【答案解析】本题译文：第二段的中心思想是鱼的质量决定了它发电的强度。本题要求理解有关材料的中心思想。这一题也要求我们运用整体理解概括出中心并注意中心与细节的区别。我们可以看到第三段只有一句话，而主句是说“电击的强度取决于鱼的大小”，随后分别以具体事实对比厂大小不同的鱼的发电量。所以B项“鱼的质量决定了它发电的强度”。反映了第三段的中心。其它三项都只描述一些细节。

单选题 The reason why the electric eel is able to give more powerful shock is that______.

【正确答案】 C

【答案解析】本题译文：电鳗能够发出更强大的电击的原因是因为与电鳐相比，电鳗的发电棱鳞的工作系统更直接和更有效。本题要求了解主要事实的细节。在第四段中，作者详细地说明了电鳗的发电系统，电鳗的发电组织是纵向的，由脊骨的神经供电，因而电流从头至尾流动。而电鳐的发电器官是蜂窝状且分布于头部两侧，可以看山电鳗由于其脊骨神经供电，电流可直接由头传至尾，较顺畅，可推断出电鳗的发电系统较之电鳐更直接也更有效一些，所以应选C项。

单选题 The ideal title for this passage is______.

【正确答案】 C

【答案解析】本题译文：本文的理想题目是发电的鱼。本题要求理解文章的中心思想。文章的题目其实也就是对全文中心的归纳，整篇文章都在叙述有关能发电的特殊鱼类及其具体发电过程。A项“电鳗”当然不正确，全文说明的鱼类不只鳗鱼一类，且重点也不是鳗鱼而是其发电系统。B项电鳐也同样不正确，C项“发电的鱼”这显然与全文主题相切，D项“电力”这与全文巾题相切，D项“电力”这与全文中心差距太大，所以应选C项。