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 defence and attack.It can be seen from the passage that（）.

r 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 (电鱼), of which several kinds live in warm seas. They posses on each side of the head, behind the eyes, a large organ consisting of a number of hexagon- al 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 centimeters 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 defence and attack.

It can be seen from the passage that ______. ()

A．the capacity to generate electricity is the distinctive characteristic of the fish

B．the current travels in an upward direction from the positive side to negative side in torpedo's electric cells

C．some fish can produce enough electricity to drive a number of electric motors

D．the torpedo's electric cells have a shape with six sides

Part A

Directions: Read the following three texts. Answer the questions on each text by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1.

The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electricmotor-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 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 (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 defence and attack.

It can be seen from the passage that ______.

A．the capacity to generate electricity is the distinctive characteristic of the fish

B．the current travels in an upward direction from the positive side to negative side in torpedo's electric cells

C．some fish can produce enough electricity to drive a number of electricmotors

D．the torpedo's electric cells have a shape with six sides

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 most 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 ceils 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 gets through from the upper, positive side of the organ downward 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 fish, but newly-born ones only about 5 centimeters 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 generate electricity for very long. People in some parts of South America who value the electric eel as food, take advantage of this fact by driving horses into the water against which the fish discharge their electricity. The horses are less affected than a man would be, and when the electric eels have exhausted themselves, they can be caught without danger.

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.

The power of producing electricity may serve these fish both for defence and attack. If a large enemy attacks, the shock will drive it away ;but it appears that the catfish and the electric eel use their current most often against smaller fish, stunning them so that they can easily be overpowered.

Which of the following can produce the strongest shock？

A．The electric eel.

B．The electric catfish.

C．The newly-born electric torpedoes.

D．The fully-grown electric ray.

nough to light lampBulbs—oreven to mn a small electric motoris almost unbelievable，but several kinds of fish are able todo this．Even more strangely。this curious power hasBeen acquired inDifferent waysBy fishBe。longing to veryDifferent families． Perhaps theBest known are the electric rays，or torpedoes(电鱼)，of which several kindslive in warm seas,They posses on each side of the head，behind the eyes，a large organ consis—ting of a number of hexagonal shaped cells rather like a honeycomb．The cells are filled with ajeUy—like substance，and contain a series of flat electric plates．One side，the negative side，ofeach plate．is supplied with very fine nerves，connected with a main nerve coming from a specialpart of theBrain．Current passes from the upper，positive side of the organDownwards to thenegative，lower side．Generally it is necessary to touch the fish in two places，completing the cir-cuit，in order to receive a shock． The strength of this shockDepends on the size of the fish，but newlyBorn ones only about5 centimeters across canBe made to light theBulb of a pocket flashlight for a few moments， while a fully grown torpedo gives a shock capable of knocking a manDown，and，if suitablewires are connected，will operate a small electric motor for several minutes． Another famous example is the electriceel．This fish gives an even more poweIful shock．The system i8Different from that of the torped。in that the electric plates run longitudinally(纵向)and ale supplied with nerves from the spinal(脊骨)cord．Consequefitly，the current passesalong the fish from head to tail．The electric or gans of these fish are really altered muscles andlike all muscles are apt(1ikely)to tire，so they are not able to produce electricity for very long．The power of producing electricity may serve these flshBom forDefence and attack． （）It canBe seen from the passage that__________．

A.the torpedo’s electric ceils have a shape with six sides

B.some fish can produce enough electricity toDrive a number of electric motors

C.the current travels in an upwardDirection from the positive side to negative sidein torpedo’s electric cells

D.the capacity to generate electricity is theDistinctive acteristic of the fish

nough to light lampBulbs—oreven to mn a small electric motoris almost unbelievable，but several kinds of fish are able todo this．Even more strangely。this curious power hasBeen acquired inDifferent waysBy fishBe。longing to veryDifferent families． Perhaps theBest known are the electric rays，or torpedoes(电鱼)，of which several kindslive in warm seas,They posses on each side of the head，behind the eyes，a large organ consis—ting of a number of hexagonal shaped cells rather like a honeycomb．The cells are filled with ajeUy—like substance，and contain a series of flat electric plates．One side，the negative side，ofeach plate．is supplied with very fine nerves，connected with a main nerve coming from a specialpart of theBrain．Current passes from the upper，positive side of the organDownwards to thenegative，lower side．Generally it is necessary to touch the fish in two places，completing the cir-cuit，in order to receive a shock． The strength of this shockDepends on the size of the fish，but newlyBorn ones only about5 centimeters across canBe made to light theBulb of a pocket flashlight for a few moments， while a fully grown torpedo gives a shock capable of knocking a manDown，and，if suitablewires are connected，will operate a small electric motor for several minutes． Another famous example is the electriceel．This fish gives an even more poweIful shock．The system i8Different from that of the torped。in that the electric plates run longitudinally(纵向)and ale supplied with nerves from the spinal(脊骨)cord．Consequefitly，the current passesalong the fish from head to tail．The electric or gans of these fish are really altered muscles andlike all muscles are apt(1ikely)to tire，so they are not able to produce electricity for very long．The power of producing electricity may serve these flshBom forDefence and attack． （）It canBe seen from the passage that__________．

A.the torpedo’s electric ceils have a shape with six sides

B.some fish can produce enough electricity toDrive a number of electric motors

C.the current travels in an upwardDirection from the positive side to negative sidein torpedo’s electric cells

D.the capacity to generate electricity is theDistinctive acteristic of the fish

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 most 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 main nerve coming from a special part of the brain. Current gets through from the upper, positive side of the organ downward 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 fish, but newly-born ones only about 5 centimeters 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 generate electricity for very long. People in some parts of South America who value the electric eel as food, take advantage of this fact by driving horses into the water against which the fish discharge their electricity. The horses are less affected than a man would be, and when the electric eels have exhausted themselves, they can be caught without danger.

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.

The power of producing electricity may serve these fish both for defence and attack. If a large enemy attacks, the shock will drive it away; but it appears that the catfish and the electric eel use their current most often against smaller fish, stunning them so that they can easily be overpowered.

Which of the following can produce the strongest shock？

A．The electric eel.

B．The electric catfish.

C．The newly-born electric torpedoes.

D．The fully-grown electric ray.

It can be seen from the passage that ______.

A．the capacity to generate electricity is the distinctive characteristic of the fish

B．the current travels in an upward direction from the positive side to negative side in torpedo's electric cells

C．some fish can produce enough electricity to drive a number of electric motors

D．the torpedo' s electric cells have a shape with six sides

The purpose of the shock produced by electric fish is to______.

A．protect themselves from being attacked

B．light up nearby waters

C．attack other fish or marine animals

D．both A and C

The main idea of the third paragraph is that ______.

A．a mature torpedo is capable of producing enough electricity to knock down a man

B．the mass of the fish decides the intensity of electric power it generates

C．the strength of shock given by a young electric ray can only light the bulb of a pocket flashlight

D．to make full use of the energy produced by electric fish, suitable wires should be available

The main idea of the third paragraph is that______.

A．a mature torpedo is capable of producing enough electricity to knock down a man

B．the mass of the fish decides the intensity of electric power it generates

C．the strength of shock given by a young electric ray can only light the bulb of a pocket flashlight

D．to make full use of the energy produced by electric fish, suitable wires should be available