[an error occurred while processing this directive]
Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells—brain cells in Alzheimer's， cardiac cells in heart disease， pancreatic cells in diabetes， to name a few； if doctors could isolate stem cells， then direct their growth， they might be able to furnish patients with healthy replacement tissue.
It was incredibly difficult， but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural， gut， muscle and bone cells. The process still can't be controlled， and may have unforeseen limitations； but if efforts to understand and master stemcell development prove successful， doctors will have a therapeutic tool of incredible power.
The same applies to cloning， which is really just the other side of the coin； true cloning， as first shown with the sheep Dolly two years ago， involves taking a developed cell and reactivating the genome within， resetting its developmental instructions to a pristine state. Once that happens， the rejuvenated cell can develop into a fullfledged animal， genetically identical to its parent.
For agriculture， in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value， biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly， and other creatures are bound to join the cloned menagerie in the coming year.
Human cloning， on the other hand， may be technically feasible but legally and emotionally more difficult. Still， one day it will happen. The ability to reset body cells to a pristine， undeveloped state could give doctors exactly the same advantages they would get from stem cells： the potential to make healthy body tissues of all sorts， and thus to cure disease. That could prove to be a true “miracle cure.”
31.The writer holds that the potential to make healthy body tissues will
[A] aggravate moral issues of human cloning
[B] bring great benefits to human beings
[C] help scientists decode body instructions
[D] involve employing surgical instruments
32.The word “rejuvenated” （Para. 5） most probably means
[A] modified[B] recollected[C] classified[D] reactivated
33.The research at the University of Wisconsin is mentioned to show
[A] the isolation of stem cells
[B] the effects of gene therapies
[C] the advantages of human cloning
[D] the limitations of tissue replacements
34.Which of the following is true according to the text？
[A] The principle of gene therapy is applicable to that of cloning.
[B] The isolation of stem cells is too difficult to be feasible.
[C] It is reasonable for all body instructions to be activated.
[D] Cloned animals will eventually take control of the world.
35.Towards the genetic research， the author's attitude can best be said to be that of
[A] frustration [B] indifference[C] amazement[D] opposition
Text 4
Nancy Casey was born in Chicago， Illinois， and left when she was three years old. Her family moved to Iowa and lived on 900 acres of farmland， where Nancy trained horses and ponies and helped raise all kinds of farm animals. Nancy loved animals then， and still has a big place in her heart for them. She currently has two Siamese cats， Misha and Iman. At sixteen years old， Nancy's family moved to California and Nancy became a big city girl. The public was very aware at the uncanny resemblance between the two divas， and Nancy was discovered as Liz at age eighteen.
In high school， Nancy was quite popular. She was a cheerleader， a school princess， she took tap， jazz， ballet and played basketball. Her junior year， she met her high school sweetheart and was married a year after graduation. At the time， she was offered a screen test from Warner Brothers films， but Nancy decided marriage was the more important choice.
Yet this untapped potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells—brain cells in Alzheimer's， cardiac cells in heart disease， pancreatic cells in diabetes， to name a few； if doctors could isolate stem cells， then direct their growth， they might be able to furnish patients with healthy replacement tissue.
It was incredibly difficult， but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural， gut， muscle and bone cells. The process still can't be controlled， and may have unforeseen limitations； but if efforts to understand and master stemcell development prove successful， doctors will have a therapeutic tool of incredible power.
The same applies to cloning， which is really just the other side of the coin； true cloning， as first shown with the sheep Dolly two years ago， involves taking a developed cell and reactivating the genome within， resetting its developmental instructions to a pristine state. Once that happens， the rejuvenated cell can develop into a fullfledged animal， genetically identical to its parent.
For agriculture， in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value， biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly， and other creatures are bound to join the cloned menagerie in the coming year.
Human cloning， on the other hand， may be technically feasible but legally and emotionally more difficult. Still， one day it will happen. The ability to reset body cells to a pristine， undeveloped state could give doctors exactly the same advantages they would get from stem cells： the potential to make healthy body tissues of all sorts， and thus to cure disease. That could prove to be a true “miracle cure.”
31.The writer holds that the potential to make healthy body tissues will
[A] aggravate moral issues of human cloning
[B] bring great benefits to human beings
[C] help scientists decode body instructions
[D] involve employing surgical instruments
32.The word “rejuvenated” （Para. 5） most probably means
[A] modified[B] recollected[C] classified[D] reactivated
33.The research at the University of Wisconsin is mentioned to show
[A] the isolation of stem cells
[B] the effects of gene therapies
[C] the advantages of human cloning
[D] the limitations of tissue replacements
34.Which of the following is true according to the text？
[A] The principle of gene therapy is applicable to that of cloning.
[B] The isolation of stem cells is too difficult to be feasible.
[C] It is reasonable for all body instructions to be activated.
[D] Cloned animals will eventually take control of the world.
35.Towards the genetic research， the author's attitude can best be said to be that of
[A] frustration [B] indifference[C] amazement[D] opposition
Text 4
Nancy Casey was born in Chicago， Illinois， and left when she was three years old. Her family moved to Iowa and lived on 900 acres of farmland， where Nancy trained horses and ponies and helped raise all kinds of farm animals. Nancy loved animals then， and still has a big place in her heart for them. She currently has two Siamese cats， Misha and Iman. At sixteen years old， Nancy's family moved to California and Nancy became a big city girl. The public was very aware at the uncanny resemblance between the two divas， and Nancy was discovered as Liz at age eighteen.
In high school， Nancy was quite popular. She was a cheerleader， a school princess， she took tap， jazz， ballet and played basketball. Her junior year， she met her high school sweetheart and was married a year after graduation. At the time， she was offered a screen test from Warner Brothers films， but Nancy decided marriage was the more important choice.