填空题 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, 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 mam 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 centimetres 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 and are supplied with nerves from the spinal 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 to tire, so they are not able to produce electricity for very long.
The electric catfish of the Nile and of other African fresh waters has a different system again, by which current passes over the whole body from the tail to the head. The shock given by this arrangement is not so strong as the other two, but is none the less unpleasant. The electric catfish is a slow, lazy fish, fond of gloomy places and grows to about 1 metre long; it is eaten by the Arabs in some areas.
判断题 Some fish produce enough electricity to drive electric motors.
【正确答案】 A
【答案解析】[解析] 根据第一段第一句内容可知,有些鱼类可以发电,甚至足以带动一个小马达,这真是不可思议,但这是事实。
判断题 Usually you will not get a shock by touching the electric ray in one place only.
【正确答案】 A
【答案解析】[解析] 根据第三段内容可知,当构成回路的时候,一条成熟的电鳐释放的电压可以击倒一个人。不过仅仅触及一点,不构成回路,就不会遭到电击。
判断题 The electric plates on the electric eel are supplied with nerves from its brain.
【正确答案】 B
【答案解析】[解析] 根据第四段内容可知,可知电鳗鱼的电板电源是来自脊椎神经而不是大脑。
判断题 The shock of the electric catfish is more unpleasant than that of the torpedo or electric eel.
【正确答案】 B
【答案解析】[解析] 根据第五段内容可知,电鲶鱼产生的电击没有电鳐鱼和电鳗鱼产生的电击强烈。
填空题 Nowadays people are making full use of these electric fish to light lamp bulbs.
填空题 complete the sentences with the information given in the passage in a maximum of 4 words.
The fish that produce electricity belong to ______.
填空题 A torpedo'hexagonal shaped cells contain a number of ______.
填空题 A fully grown torpedo can give a ______ than a young one.
填空题 The catfish's electric current passes from the ______.
填空题 The electric fish produce electricity mainly for ______.