As if there weren’t enough of them in the world already, scientists have succeeded in cloning flies. The alike fruit flies are the first insects ever cloned, says the Canadian team that created them. The question everyone asks is why anyone would want to clone flies in the first place. She hopes that the insects , which are very easy to experiment with , will help to adjust the cloning process in other animals and even in humans, where the technique is being researched to aid production of therapeutic (治疗的) stem cells.
In cloning, the DNA-containing nucleus of an adult cell is injected into an egg whose own nucleus(细胞核) has been removed. At the moment, the majority of cloned mice, sheep and other animals die before birth. It is thought this is because the adult DNA is not properly ‘reprogrammed’.
Using flies, researchers might discover genes that are important for this reprogramming, and that have matches in other animals. That is because it is relatively easy in flies to knock out the function of a single gene and then attempt cloning with these cells, which will test whether that gene is important. If such genes are confirmed, then in theory cloned mammalian embryos(晶胚) might be grown in selected solutions that change the activity of those genes to improve the technique’s success rate. Although some groups have attempted to clone insects before, Lloyd says this is the first time it has been successful. The team used a slight difference on the standard cloning process: they transferred nuclei taken from embryos rather than fully-grown adult cells. They sucked several nuclei (pl)out of developing fly embryos, and injected them into a fertilized(已受精的) fly egg. From over 800 early attempts, they cloned five adult insects, the group reports in the journal Genetics.
【小题1】The best title of this passage probably is _______.

As if there weren’t enough of them in the world already, scientists have succeeded in cloning flies. The alike fruit flies are the first insects ever cloned, says the Canadian team that created them. The question everyone asks is why anyone would want to clone flies in the first place. She hopes that the insects , which are very easy to experiment with , will help to adjust the cloning process in other animals and even in humans, where the technique is being researched to aid production of therapeutic (治疗的) stem cells.
In cloning, the DNA-containing nucleus of an adult cell is injected into an egg whose own nucleus(细胞核) has been removed. At the moment, the majority of cloned mice, sheep and other animals die before birth. It is thought this is because the adult DNA is not properly ‘reprogrammed’.
Using flies, researchers might discover genes that are important for this reprogramming, and that have matches in other animals. That is because it is relatively easy in flies to knock out the function of a single gene and then attempt cloning with these cells, which will test whether that gene is important. If such genes are confirmed, then in theory cloned mammalian embryos(晶胚) might be grown in selected solutions that change the activity of those genes to improve the technique’s success rate. Although some groups have attempted to clone insects before, Lloyd says this is the first time it has been successful. The team used a slight difference on the standard cloning process: they transferred nuclei taken from embryos rather than fully-grown adult cells. They sucked several nuclei (pl)out of developing fly embryos, and injected them into a fertilized(已受精的) fly egg. From over 800 early attempts, they cloned five adult insects, the group reports in the journal Genetics.
【小题1】The best title of this passage probably is _______.

As if there weren’t enough of them in the world already, scientists have succeeded in cloning flies. The alike fruit flies are the first insects ever cloned, says the Canadian team that created them. The question everyone asks is why anyone would want to clone flies in the first place. She hopes that the insects , which are very easy to experiment with , will help to adjust the cloning process in other animals and even in humans, where the technique is being researched to aid production of therapeutic (治疗的) stem cells.

In cloning, the DNA-containing nucleus of an adult cell is injected into an egg whose own nucleus(细胞核) has been removed. At the moment, the majority of cloned mice, sheep and other animals die before birth. It is thought this is because the adult DNA is not properly ‘reprogrammed’.

Using flies, researchers might discover genes that are important for this reprogramming, and that have matches in other animals. That is because it is relatively easy in flies to knock out the function of a single gene and then attempt

cloning with these cells, which will test whether that gene is important. If such genes are confirmed, then in theory cloned mammalian embryos(晶胚) might be grown in selected solutions that change the activity of those genes to improve the technique’s success rate. Although some groups have attempted to clone insects before, Lloyd says this is the first time it has been successful. The team used a slight difference on the standard cloning process: they transferred nuclei taken from embryos rather than fully-grown adult cells. They sucked several nuclei (pl)out of developing fly embryos, and injected them into a fertilized(已受精的) fly egg. From over 800 early attempts, they cloned five adult insects, the group reports in the journal Genetics.

67.The best title of this passage probably is _______.

A. The importance of clone

B. First insects are cloned

C. The disagreement in clone

D. The advantages of clone

68. The scientists cloned flies because________.

     A. there are fewer and fewer flies in the world 

B. flies are easy to find and cheap to use

     C. they can gain some experience before cloning other animals

     D. it is safe to cline flies

69. The failure of most cloned animals is due to _______.

   A. the difference of other animals’ genes

   B. the improper technique of clone

   C. the complex of other animals

   D. the improper rearrange of the adult gene

70. It can be inferred from the last paragraph that ______.

     A. the clone of insects before used grown-up cells

  B. the clone of insects were never experimented before  

C. this time scientists cloned flies successfully and easily

      D. based on this success, other animals will be cloned in large quantities. 

    British scientists have done something that，many people thought，was impossible: they created the first clone of an adult mammal（哺乳动物）．The clone，named Dolly，is a seven-month-old sheep，grown from a cell of an adult female sheep.

    What is a clone? A clone is a copy—a genetic copy. Genes are the instructions for life. They tell a cell what to do and how to do it. Genes make each individual plant or animal different and unique. But a clone has the same genes as the original organism(生物体）．

    Cloning is not new. Plants have been cloned for centuries. New plants are often grown from cutting from another plant. Also，plants like pineapples，strawberries and carnations(康乃馨）are sometimes cloned. One benefit of cloning is that we can make many copies of the best and healthiest plants.

    It has been much more difficult to clone animals. Frogs have been cloned，but they died as tadpoles，never living long enough to become adult frogs，which made the scientists despondent. Mice，sheep and cattle have been cloned from embryos. But Dolly is the first healthy clone of an adult mammal. How did they do it?

    （1）An unfertilized egg was taken from a sheep.

    （2）The egg nucleus(细胞核）was removed.

    （3)A cell was taken from the udder(乳房）of a pregnant(怀孕的）sheep. It was“starved”，so that it stopped growing.

    （4）The two cells were combined into one，and then implanted in a third sheep，where it grew normally.

    （5）The clone was born. It was genetically identical to the pregnant sheep.

    This sounds much easier than it actually was. To end up with one clone，the scientists started with 277 udder cells. And they needed in a way to make the egg cell accept a new nucleus. They did that by starving the cell.

    It may soon be possible to clone many types of animals. Will we also be able to clone human organs，or even whole human beings? We have only begun to think about the morality of cloning technology. Maybe the question to ask is not whether we can clone humans，but instead，should we clone humans?

59. What can replace the underlined word“despondent” in the fourth paragraph?

A. calmed down          B. set down

C. cut down             D. cast down

60. Dolly is a sheep________because she is grown from a cell of an adult female sheep.

A. that has no father         B. that has no mother

C. that has no parents        D. that has no tail

61. According to the passage we can know that__________．

A. only plants can be cloned

B. only strawberries and carnations can sometimes be cloned

C. animals and plants have quite a long history of cloning

D. genes can tell a cell what to do and how to do it during cloning

62. From the fourth paragraph we can know that__________．

A. a tadpole is the early stage of a grown-up frog

B. a tadpole is a frog without a tail

C. a tadpole is a kind of animal

D. a tadpole is a clone of an adult mammal

As if there weren’t enough of them in the world already, scientists have succeeded in cloning flies. The alike fruit flies are the first insects ever cloned, says the Canadian team that created them. The question everyone asks is why anyone would want to clone flies in the first place. She hopes that the insects , which are very easy to experiment with , will help to adjust the cloning process in other animals and even in humans, where the technique is being researched to aid production of therapeutic (治疗的) stem cells.
In cloning, the DNA-containing nucleus of an adult cell is injected into an egg whose own nucleus(细胞核) has been removed. At the moment, the majority of cloned mice, sheep and other animals die before birth. It is thought this is because the adult DNA is not properly ‘reprogrammed’.
Using flies, researchers might discover genes that are important for this reprogramming, and that have matches in other animals. That is because it is relatively easy in flies to knock out the function of a single gene and then attempt cloning with these cells, which will test whether that gene is important. If such genes are confirmed, then in theory cloned mammalian embryos(晶胚) might be grown in selected solutions that change the activity of those genes to improve the technique’s success rate. Although some groups have attempted to clone insects before, Lloyd says this is the first time it has been successful. The team used a slight difference on the standard cloning process: they transferred nuclei taken from embryos rather than fully-grown adult cells. They sucked several nuclei (pl)out of developing fly embryos, and injected them into a fertilized(已受精的) fly egg. From over 800 early attempts, they cloned five adult insects, the group reports in the journal Genetics.

1. 1.

   The best title of this passage probably is _______.

   1. A.
      The importance of clone
   2. B.
      First insects are cloned
   3. C.
      The disagreement in clone
   4. D.
      The advantages of clone
2. 2.

   The scientists cloned flies because________.

   1. A.
      there are fewer and fewer flies in the world
   2. B.
      flies are easy to find and cheap to use
   3. C.
      they can gain some experience before cloning other animals
   4. D.
      it is safe to clone flies
3. 3.

   The failure of most cloned animals is due to _______.

   1. A.
      the difference of other animals’ genes
   2. B.
      the improper technique of clone
   3. C.
      the complex of other animals
   4. D.
      the improper rearrange of the adult gene
4. 4.

   It can be inferred from the last paragraph that ______.

   1. A.
      the clone of insects before used grown-up cells
   2. B.
      the clone of insects were never experimented before
   3. C.
      this time scientists cloned flies successfully and easily
   4. D.
      based on this success, other animals will be cloned in large quantities.