Like distance runners on a measured course，all of us will move through time in a roughly predictable pattern．

In the first stage of our lives，we develop and grow, reaching toward the top of physical vitality(活力)．

After we grow up，however, the body begins a process of gradually wearing out．

A new awareness of physical fitness may help lengthen our years of health and vitality，yet nothing we do will work to stop the unavoidable force of aging．

Most of the changes of aging take place deep inside the body．The lungs become less able to take in oxygen．Powerful muscles gradually lose their strength．The heart loses power and pumps less blood．Bones grow easier to break．

Finally, we meet a stress，a stress that is greater than our physical resistance．Often，it is only a minor accident or chance infection(a disease caused by virus)，but this time，it brings life to an end．

In 1932，a classic experiment nearly doubled the lifetime of rats，simply by cutting back the calories in their diet The reason for the effect was then unknown．

Today, at the University of California at Berkley, Dr．Paul Seagle has also greatly lengthened the normal lifetime of rats．The result was achieved through a special protein limited diet，which had a great effect on the chemistry of the brain．Seagle showed that within the brain，specific chemicals control many of the signals that influence aging．By changing that chemical balance，the clock of aging can be reset．

For the first time, the mystery of why we age is being seriously challenged．Scientists in many fields are now making striking and far-reaching discoveries．

An average lifetime lasts 75 years，yet in each of us lies a potential for a longer life．If we could keep the vitality and resistance to disease that we have at age twenty, we would live for 800 years．

1.What does the underlined word “it” refer to?

A．Physical vitality．   B．Stress．           C．Aging．           D．Physical resistance．

2.Which of the following is not a change of aging?

A．People gradually lose their muscle strength．

B．Bones tend to break more easily．

C．The heart loses power and pumps less blood．

D．The lungs become unable to take in oxygen．zxxk

3.The author believes the following except that     ．

A．human's life pattern is predictable

B．physical fitness can't stop the force of aging

C．human's lifetime will last longer than 75 years

D．all of the changes of aging take place deep inside the body

4.How did Dr．Paul Seagle lengthen the lifetime of rats in his experiment?

A．By keeping their physical fitness．          B．By cutting the calories in their diet．

C．By resetting their clock of aging．           D．By limiting the protein in their diet．

5.What is probably the best title for the article?

A．Two Great Experiments

B．The Mystery of Human Life

C．The Breakthrough in the Study of Aging

D．Ways to lengthen Human Life

Like distance runners on a measured course，all of us will move through time in a roughly predictable pattern．
In the first stage of our lives，we develop and grow, reaching toward the top of physical vitality(活力)．
After we grow up，however, the body begins a process of gradually wearing out．
A new awareness of physical fitness may help lengthen our years of health and vitality，yet nothing we do will work to stop the unavoidable force of aging．
Most of the changes of aging take place deep inside the body．The lungs become less able to take in oxygen．Powerful muscles gradually lose their strength．The heart loses power and pumps less blood．Bones grow easier to break．
Finally, we meet a stress，a stress that is greater than our physical resistance．Often，it is only a minor accident or chance infection(a disease caused by virus)，but this time，it brings life to an end．
In 1932，a classic experiment nearly doubled the lifetime of rats，simply by cutting back the calories in their diet The reason for the effect was then unknown．
Today, at the University of California at Berkley, Dr．Paul Seagle has also greatly lengthened the normal lifetime of rats．The result was achieved through a special protein limited diet，which had a great effect on the chemistry of the brain．Seagle showed that within the brain，specific chemicals control many of the signals that influence aging．By changing that chemical balance，the clock of aging can be reset．
For the first time, the mystery of why we age is being seriously challenged．Scientists in many fields are now making striking and far-reaching discoveries．
An average lifetime lasts 75 years，yet in each of us lies a potential for a longer life．If we could keep the vitality and resistance to disease that we have at age twenty, we would live for 800 years．
【小题1】What does the underlined word “it” refer to?

It was the district sports meet. My foot still hadn’t healed(痊愈) from a(n) ___36___ injury. I had___37___ whether or not I should attend the meet. But there I was, ___38___for the 3,000-meter run.

“Ready…set…” The gun popped and we were off. The other girls rushed ___39___ me. I felt ___40___ as I fell farther and farther behind.

“Hooray!” shouted the crowd. It was the loudest___41___ I had ever heard at a meet. The first-place runner was two laps（圈）ahead of me when she crossed the finish line.

“Maybe I should___42___, I thought as I moved on. ___43___, I decided to keep going. During the last two laps, I ran ___44___ and decided not to ___45___in track next year. It wouldn’t be worth it, ___46___my foot did heal.

When I finished, I heard a cheer--___47___ than the one I’d heard earlier. I turned around and___48___, the boys were preparing for their race. “They must be cheering for the boys. ”

I was leaving ___49___ several girls came up to me. “Wow, you’ve got courage!” one of them told me.

“Courage? I just ___50___a race!” I thought.

“I would have given up on the first lap,” said another girl. “We were cheering for you. Did you hear us?”

Suddenly I regained___51___. I decided to ___52___ track next year. I realized strength and courage aren’t always ___53___ in medals and victories, but in the ___54___we overcome(战胜). The strongest people are not always the people who win, ___55___ the people who don’t give up when they lose.

36. A. slighter B. worse  C. earlier D. heavier

37. A. expected      B. supposed    C. imagined    D. doubted

38. A. late      B. eager  C. ready  D. thirsty

39. A. from behind B. ahead of     C. next to       D. close to

40. A. ashamed      B. astonished  C. excited       D. frightened

41. A. cheer    B. shout  C. cry     D. noise

42. A. slow down   B. drop out     C. go on  D. speed up

43. A. Therefore     B. Otherwise   C. Besides      D. However

44. A. with delight B. with fear    C. in pain       D. in advance

45. A. play     B. arrive  C. race    D. attend

46. A. even if  B. only if       C. unless D. until

47. A. weaker B. longer C. lower  D. louder

48. A. well enough B. sure enough       C. surprisingly enough   D. strangely enough

49. A. while    B. when  C. as       D. since

50. A. finished       B. won    C. passed D. lost

51. A. cheer    B. hope   C. interest       D. experience

52. A. hold on B. turn to       C. begin with  D. stick with

53. A. measured     B. praised       C. tested  D. increased

54. A. sadness B. struggles    C. diseases      D. tiredness

55. A. or B. nor     C. and     D. but

 A big earthquake __________7.1 on the Richter scale struck Yushu, knocking down buildings and causing more than two thousands people to lose their lives．

A. measured                       B. measuring            C. to be    measured                  D. measures

 It was the district sports meet. My foot still hadn’t healed(痊愈)from a(n) ___1___ injury. I had ___2___ whether or not I should attend the meet. But there I was, ___3___ for the 3,000-meter run.

“Ready … set …” The gun popped and we were off. The other girls rushed ___4___ me. I felt ___5___ as I fell farther and farther behind.

“Hooray!” shouted the crowd. It was the loudest ___6___ I had ever heard at a meet. The first-place runner was two laps (圈) ahead of me when she crossed the finish line. “Maybe I should ___7___,” I thought as I moved on. ___8___, I decided to keep going. During the last two laps, I ran ___9___ and decided not to ___10___ in track next year. It wouldn’t be worth it, ___11___ my foot did heal.

 When I finished, I heard a cheer— ___12___ than the one I’d heard earlier. I turned around and ___13___, the boys were preparing for their race. “They must be cheering for the boys.” I was leaving ___14___ several girls came up to me. “Wow, you’ve got courage!” one of them told me.

“Courage? I just ___15___ a race!” I thought. “I would have given up on the first lap,” said another girl. “We were cheering for you. Did you hear us?”

Suddenly I regained ___16___. I decided to ___17___ track next year. I realized strength and courage aren’t always ___18___ in medals and victories, but in the ___19___ we overcome(战胜). The strongest people are not always the people who win, ___20___ the people who don’t give up when they lose.

1. A. slighter  B. worse     C. earlier    D. heavier

2. A. expected      B. supposed    C. imagined   D. doubted

3. A. late    B. eager   C. ready     D. thirsty

4. A. from behind   B. ahead of  C. next to   D. close to

5. A. ashamed B. astonished  C. excited D. frightened

6. A. cheer     B. shout  C. cry    D. noise

7. A. slow down     B. drop out    C. go on  D. speed up

8. A. Therefore   B. Otherwise   C. Besides   D. However

9. A. with delight    B. with fear  C. in pain    D. in advance

10. A. play     B. arrive   C. race  D. attend

11. A. even if   B. only if  C. unless   D. until

12. A. weaker     B. longer      C. lower  D. louder

13. A. well enough     B. sure enough   

   C. surprisingly enough   D. strangely enough

14. A. while       B. when    C. as     D. since

15. A. finished   B. won    C. passed      D. lost

16. A. cheer   B. hope   C. interest   D. experience

17. A. hold on   B. turn to   C. begin with    D. stick with

18. A. measured   B. praised   C. tested  D. increased

19. A. sadness     B. struggles    C. diseases   D. tiredness

20. A. or     B. nor    C. and     D. but