Science seems to be getting closer to answering a very old mystery. Homing pigeons can be 　36　 hundreds of miles from their homes. When they are let to go to 　37　 again, they find their way home. Because of this special ability to 　38　,pigeons have been used 　 39　 messengers for hundreds of years.

Today people even breed homing pigeons for 　40　 at a sport. The birds are shipped to some chosen 　41　 a few hundred miles away. Then all of them are let to go together. The winner is the bird that gets home 　42　.A good race can make it home from 500 miles away 　43　 a single day.

　 The mystery of the homing pigeons is how they 　 44　 directions and how they find home. The first part seems to be pretty well 　 45　,and we know of two ways that pigeons tell directions. First, they use the sun. Experiments show that homing pigeons can tell 　46　 by the sun. What happens when the 　47　 is darkly overcoat by clouds and no one can 　48　 where the sun is? Then the pigeons still find their way home.

　Naturally, people have wondered whether pigeons might have a built-in compass　 49　 that would tell them about the direction of the 　　 50 　 magnetic(磁的)field. Many different kinds of experiments were 　 51　 　.Here’s what the scientists decided 　 52　 they had made experiments many times. When pigeons can see the sun, they use it as their 　 　53　 　 means of direction-finding. When they can’t see the sun, they use some 　54　 way to sense direction from the earth’s magnetic field.

　 But how do pigeons know 　55　 direction is toward home? What do they use that we would call a map? These are other questions to be answered.

36. A. carried B. taken　　　　 　　　　　　 C. shipped　　　　 　　　　 D. brought

37. A. escape B. get　　　　　 　　　 C. fly　　　　　　　　　　　　　　　　 D. run

38. A. find home B. sense directions　 C. send messages　　　 D. make friends

39. A.by B. as　　　　　　　　　　 C. for　　　　　 　　　　　　　　　　 D. to

40.A.performing B. directing　　　　　 C. showing　　　 　　　　 D. racing

41.A.place B. port　　　　　　　　 C. city　　　　　　　　　　　　 D. country

42.A.fast B. quickly　　　　　　 C. safely　　　　 　　　　　　　　　 D. first

43.A.on B. at　　　　　　　　　　 C. in　　　　　　 　　　　　　　 D. over

44.A.tell B. recognize　　　　　　　　 C. realize　　　 　　　　　　 D. know

45.A.explained B. answered　　 　　 C. shown　　　　　　　　　　 D. understood

46.A.courses B. roads　　　　　　　 C. directions　　 　　　　　 D. ways

47.A.sun B. heaven　　　　　　　　　　 C. land　　　　　　　　　　　　　　　 D. sky

48.A.see B. find　　　　　　　　　 C. notice　　　　　　　　　　　　　　 D. observe

49.A.anything B. something　 　　 C. someone　　　　　　　　 D. anyone

50.A.earth’s B. sun’s　　　　　　　　 C. planet’s　　　　　　　　　　　　　 D. destination’s

51.A.carried B. done　　　　　　　　 C. taken　　　　　　　　　　　　　　 D. had

52.A.before B. when　　　　　　　　　　　 C. while　　　　　　　　　　　　　　 D. after

53.A.important B. major　　　　　　　 C. main　　　　　　　　　　　　　　　 D. most

54.A.quick B. strange　　　　　　 C. special　　　　　　　　　　　　　 D.easy

55.A.what B. where　　　　　　　　　　 C. how　　　　　　　　　　　　　　　 D. which

　　The mother rushes her three-year-old son to the hospital's emergency room.

　　“My baby has a very high fever, ”she explains, “He is 1 all over.”

　　The doctor examines the boy right away. He draws a sample of 2 from the baby's arm, and rushes it over to the 3 . The lab worker places it in a large 4 with a built-in computer.

　　In less than a minute the machine tests the blood and 5 out the results . The doctor reads the 6 .They tell him what is wrong with the child. He gives the child an injection. Half an hour later the boy is playing and smiling.

　　To the police officers in the Patrol car, it looks like a typical case of a car 7 a red light. They 8 their flashing lights, and 9 to catch the car. But the other 10 begins going even faster.

　　“This might mean trouble , ”says one of the officers, “ 11 the license on the computer. See what you get.”

　　Green letters start to 12 words on the small screen. “Stolen car. Used in armed robbery. 13 ”

　　The police car pulls 14 . It forces the other car to 15 . The two officers come out with drawn pistols(手枪). They arrest the driver, and bring him to the police station for 16 .

　　Carla and three of her friends decide to go to a New York Jets football game on Sunday afternoon. But no one has any money . All the banks are closed .

　　Carla , though , has a special bank 17 . She goes to the closed bank office . Placing her card in 18 on the outside of the bank, she types in various numbers on the keyboard below.

　　The keyboard sends a message to the bank' s computer . The computer automatically (自动地) takes the money from her account . It pushes out the 19 through another opening in the wall .

　　Computers are changing the way we live . In fact, no matter what you do, or where you do it, you can be sure that there is a 20 in your life .

1．

[　　]

2．

[　　]

3．

[　　]

4．

[　　]

5．

[　　]

6．

[　　]

7．

[　　]

8．

[　　]

9．

[　　]

10．

[　　]

11．

[　　]

12．

[　　]

13．

[　　]

14．

[　　]

15．

[　　]

16．

[　　]

17．

[　　]

18．

[　　]

19．

[　　]

20．

[　　]

Water costs money．In some places water is hard  36  ．What  37when a town

has these problems？A small town in California found a happy   38 ．

　　Very 39 rain ever fell there．The town had no water  40  ．The water it used was  41  from a river 300 miles away．As more people  42  live in the town，   43   water was needed．Now water  44  to be brought in from 600 miles away．All these cost  45 money．

　　The town 46 a plan．It found 47  to clean its “dirty” water．Once the cleaned water was reused   48  many ways．Five  49  lakes were built．Here people could swim and fish and go   50  ．They  51  have picnics in their new parks．Farmers had more water  52 their crops．New factories can be built，now that they have the promise of  53  ．

　　In most places，water is used and thrown 54 ．The town that saved  55  water

has saved the town！

A．supplying     B．getting              C．to get         D．to supply

A．happens       B．happening    C is happened             D．happened

A．key           B．answer       C answering          D．way

A．little         B．a little          C．few            D．a few

A．of itself       B．of its own       C．for its own     D for itself

A．fetch          B．take         C．brought in      D．guided

A．come to     B．came to      C．coming to      D．came for

A．many      B．plenty  of    C．more            D．many more

A．has           B．had             C．must             D．needed

A．many        B．a few         C．a great many   D．a lot of

A．put          B．made           C．supply        D．noticed

A．a way       B．ways           C．an answer     D．a key

A．for           B．by             C．at             D．in

A．man-making                B．man-make 

            C．man-made                   D．man made

A．boating     B．to boat          C．to boating       D．on boating

A．must       B．could          C．needed          D．had to

A．as           B．with            C．for           D．to

A．water enough               B．enough water  

          C. crops enough                 D．enough crops

A．off       B．of             C．away        D．out of

A．it’s         B．its              C．one’s           D．his