British scientists have done something that,many people thought,was impossible: they created the first clone of an adult mammal(哺乳動物).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(生物體).

    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(細(xì)胞核)was removed.

    (3)A cell was taken from the udder(乳房)of a pregnant(懷孕的)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

59. 【解析】選D。詞義理解題。由第四段前兩句可推知科學(xué)家們很不高興。cast down“使沮喪;使不愉快”。

60. 【解析】選C。推理判斷題。從文中可以看出,多莉是從一只成年羊的細(xì)胞中克隆出來的,所以它沒有父母,而是那只羊的一個翻版。

61. 【解析】選D。細(xì)節(jié)理解題。D項“基因在克隆過程中可以告訴細(xì)胞做什么及如何去做”,文章第二段正是說的這個意思。第三段指植物可以克隆,第四段指動物也可以克隆,所以A項不正確;從文中第三段可知菠蘿也是可以克隆的,所以B項不正確;第三段中指植物已有幾個世紀(jì)的克隆歷史,而沒有提到動物的克隆歷史,所以C項與題意不符。

62.【解析】選A。推理判斷題。文章第四段第二句說:人們曾經(jīng)克隆過青蛙,但在蝌蚪階段就死了,并沒有進入成年青蛙階段,所以我們可以判斷,蝌蚪是青蛙的早期形態(tài)。

 

練習(xí)冊系列答案
相關(guān)習(xí)題

科目:高中英語 來源:2011-2012學(xué)年山西大學(xué)附屬中學(xué)高三4月月考英語試卷(帶解析) 題型:閱讀理解

Australian Flag Designs by Readers of the Sun-Herald
We received dozens of responses after inviting readers to send in their designs for a new flag. The designs we received include:
James Anthony, Drummoyne
James reduces the Union Jack down in size and changes its shape to become a reminder of the British tradition rather than canceling it altogether. At the same time he suggests enlarging the stars of the Southern Cross. His design attempts to use the best of both worlds in a newly designed flag.
As he says, “the British part of the Australian Flag is too big and the Australian bits are too small. When you make the stars bigger the Australian flag can look impressive.”
Joe Bollen, Turranmurra
Joe’s flag has the main elements of a risen sun, white horizon(地平線), red earth at the base and the Southern Cross. He intends to make the risen sun a special Australian symbol on the flag. He believes it represents life. The Southern Cross shows that we live in the Southern Hemisphere. (半球)
Maria Ieraci, Sydney
Maria deleted the Union Jack but otherwise kept the flag as is with the Southern Cross and Federation Star. She says, ‘There is only one correct way to change the Australian flag” and that is “to drop the Union Jack ---- when Australia becomes a Republic”, which she hopes will be before 2010.
Ron Bennett, Sydney
Ron recommends using the Aboriginal colors but replacing their image of the sun with the map of Australia. He says, “Australia is unique being an island continent with an instantly recognizable outline at that” and “this will leave no doubt as to which country the flag belongs.”
【小題1】Which of the four designs can remind you of the past of the country?

A.Joe’sB.Maria’sC.Ron’sD.Jame’s
【小題2】The Southern Cross in some of the designs represents _________.
A.the spirit of the nation
B.the position of the country
C.the tradition of Britain
D.the expectations of the people
【小題3】What does the Union Jack refer to?
A.the British flag
B.A former British ruler
C.group of stars
D.A former symbol of Australia

查看答案和解析>>

科目:高中英語 來源:2011-2012學(xué)年江蘇南京師大附中江寧分校高二下期末調(diào)研英語試卷(帶解析) 題型:閱讀理解

Robert Frost was one of America’s best known and most honored serious writers. But his fame came late in his life.
He was born in San Francisco, California in 1874. He lived in California during his early childhood. He was named after the chief Southern general in America’s Civil War. The general’s name was Robert Edward Lee. The poet was named Robert Lee Frost, because his father wanted to honor the general.
Someone once asked another American writer, Ernest Hemingway, how to become a writer. The best thing, he said, was to have an unhappy childhood. If this is true, Robert Frost’s childhood was unhappy enough to make him a very good writer. Robert Frost’s father was a reporter who wanted to be a politician. He often drank too much wine and became angry. Robert was the victim of his anger.
Robert Frost finished high school in 1891. After high school, Robert’s grandfather offered to pay his costs at Dartmouth College. But Robert left the school after a few months. He did not like it. He spent the next few years working at different jobs. At one time, he worked in a factory. Later, he repaired shoes. He was a teacher. He was a reporter. Always, he wrote poetry.
Robert Frost attended Harvard University for two years. After that, he returned to the many jobs he held before. For a while, Frost tried to take care of a farm in the state of New Hampshire. He was not a successful farmer. And he continued to write poetry. He said that until 1930, he earned only about ten dollars a year from writing.
In 1912, he decided to try to make a new start. He took his family to Britain. The cost of living was low. In Britain, Frost found a publisher for his first book of poems. The book was called A Boy’s Will. When it appeared in 1913, Frost received high praise from British readers. Praise was something he had not received in his own country.
Ezra Pound, another American poet living in Britain, read the poems and liked them very much. He wrote a magazine article about Frost. He also helped get Frost’s second book of poems published in America. That book was called North of Boston.
【小題1】The followings are writers EXCEPT __________.

A.Robert Edward LeeB.Robert Lee Frost
C.Ernest HemingwayD.Ezra Pound
【小題2】The passage wrote about Hemingway in order to show that __________.
A.he had great influence on Frost’s poetry and life
B.Frost’s poetry style was the same as Hemingway’s
C.Frost was unhappy because he was the victim of his father
D.Frost spent his childhood unhappily
【小題3】What can we learn from the passage?
A.Once Frost’s first book was published he gained great praise in his country.
B.After leaving Harvard University, he began to learn to write poetry.
C.Frost was found lo have a gift in poetry while he studied in high school.
D.Robert Frost’s father was angry and drank a lot because he didn’t realize his dream.
【小題4】What’s the passage mainly about?
A.Robert Frost’s unhappy childhood.
B.Robert Frost’ s first and second book.
C.Robert Frost’s family and jobs.
D.Robert Frost’s life and poetry.

查看答案和解析>>

科目:高中英語 來源:2012-2013學(xué)年四川省雅安中學(xué)高一10月月考英語試卷(帶解析) 題型:閱讀理解

Robert Frost was one of America’s best known and most honored serious writers. But his fame came late in his life.
He was born in San Francisco, California in 1874. He lived in California during his early  childhood. He was named after the chief Southern general in America’s Civil War. The general’s name was Robert Edward Lee. The poet was named Robert Lee Frost, because his father wanted to honor the general.
Someone once asked another American writer, Ernest Hemingway, how to become a writer. The best thing, he said, was to have an unhappy childhood. If this is true, Robert Frost’s childhood was unhappy enough to make him a very good writer. Robert Frost’s father was a reporter who wanted to be a politician. He often drank too much wine and became angry. Robert was the victim (受害者) of his anger.
Robert Frost finished high school in 1891. After high school, Robert’s grandfather offered to pay his costs at Dartmouth College. But Robert left the school after a few months. He did not like it. He spent the next few years working at different jobs. At one time, he worked in a factory. Later, he repaired shoes. He was a teacher. He was a reporter. Always, he wrote poetry.
Robert Frost attended Harvard University for two years. After that, he returned to the many jobs  he held before. For a while, Frost tried to take care of a farm in the state of New Hampshire. He was not a successful farmer. And he continued to write poetry. He said that until 1930, he earned only about ten dollars a year from writing.
In 1912, he decided to try to make a new start. He took his family to Britain. The cost of living was low. In Britain, Frost found a publisher for his first book of poems. The book was called A Boy’s Will. When it appeared in 1913. Frost received high praise from British readers. Praise was something he had not received in his own country.
Ezra Pound, another American poet living in Britain, read the poems and liked them very much. He wrote a magazine article about Frost. He also helped get Frost’s second book of poems published in America. That book was called North of Boston.
【小題1】The followings are writers EXCEPT ________.

A.Robert Edward LeeB.Robert Lee Frost
C.Ernest Hemingway D.Ezra Pound
【小題2】The passage wrote about Hemingway in order to show that
A.he had great influence on Frost’s poetry and life
B.Frost’ s poetry style was the same as Hemingway’s
C.Frost was unhappy because he was the victim of his father
D.Frost spent his childhood unhappily
【小題3】What can we learn from the passage?
A.Once Frost’s first book was published he gained great praise in his country.
B.After leaving Harvard University, he began to learn to write poetry.
C.Frost was found lo have a gift in poetry while he studied in high school.
D.Robert Frost’s father was angry and drank a lot because he didn’t realize his dream.
【小題4】What’s the passage mainly about?
A.Robert Frost’s unhappy childhood.B.Robert Frost’s first and second book.
C.Robert Frost’s family and jobs.D.Robert Frost’s life and poetry.

查看答案和解析>>

科目:高中英語 來源:2012-2013學(xué)年四川省雅安中學(xué)高一上學(xué)期10月月考英語試卷(帶解析) 題型:閱讀理解

Robert Frost was one of America’s best known and most honored serious writers. But his fame came late in his life.
He was born in San Francisco, California in 1874. He lived in California during his early  childhood. He was named after the chief Southern general in America’s Civil War. The general’s name was Robert Edward Lee. The poet was named Robert Lee Frost, because his father wanted to honor the general.
Someone once asked another American writer, Ernest Hemingway, how to become a writer. The best thing, he said, was to have an unhappy childhood. If this is true, Robert Frost’s childhood was unhappy enough to make him a very good writer. Robert Frost’s father was a reporter who wanted to be a politician. He often drank too much wine and became angry. Robert was the victim (受害者) of his anger.
Robert Frost finished high school in 1891. After high school, Robert’s grandfather offered to pay his costs at Dartmouth College. But Robert left the school after a few months. He did not like it. He spent the next few years working at different jobs. At one time, he worked in a factory. Later, he repaired shoes. He was a teacher. He was a reporter. Always, he wrote poetry.
Robert Frost attended Harvard University for two years. After that, he returned to the many jobs  he held before. For a while, Frost tried to take care of a farm in the state of New Hampshire. He was not a successful farmer. And he continued to write poetry. He said that until 1930, he earned only about ten dollars a year from writing.
In 1912, he decided to try to make a new start. He took his family to Britain. The cost of living was low. In Britain, Frost found a publisher for his first book of poems. The book was called A Boy’s Will. When it appeared in 1913. Frost received high praise from British readers. Praise was something he had not received in his own country.
Ezra Pound, another American poet living in Britain, read the poems and liked them very much. He wrote a magazine article about Frost. He also helped get Frost’s second book of poems published in America. That book was called North of Boston.
【小題1】The followings are writers EXCEPT ________.

A.Robert Edward LeeB.Robert Lee Frost
C.Ernest Hemingway D.Ezra Pound
【小題2】The passage wrote about Hemingway in order to show that
A.he had great influence on Frost’s poetry and life
B.Frost’ s poetry style was the same as Hemingway’s
C.Frost was unhappy because he was the victim of his father
D.Frost spent his childhood unhappily
【小題3】What can we learn from the passage?
A.Once Frost’s first book was published he gained great praise in his country.
B.After leaving Harvard University, he began to learn to write poetry.
C.Frost was found lo have a gift in poetry while he studied in high school.
D.Robert Frost’s father was angry and drank a lot because he didn’t realize his dream.
【小題4】What’s the passage mainly about?
A.Robert Frost’s unhappy childhood.B.Robert Frost’s first and second book.
C.Robert Frost’s family and jobs.D.Robert Frost’s life and poetry.

查看答案和解析>>

科目:高中英語 來源:2012-2013學(xué)年福建省德化一中高三9月聯(lián)考英語試卷(解析版) 題型:閱讀理解

 

Most of my earliest childhood memories are of the beach — in the hot sun, building sandcastles, burying Dad in the sand.

Now the coast has a pleasant and relaxing attraction beyond words. I look forward to a windy cliff-top walk or a rainy day rock-picking just as much as those rare moments when I get to a short sleep in the sun. But there’s nothing more pleasurable than turning up at a beach to find it deserted.

These are my favourite secret beaches — ones either not well known or take a bit of effort to get to. Most of those listed scored highly in the Marine Conservation Society Good Beach Guide 2009; the others are too secret even for them.

Sennen Clove is just a mile northeast of Land’s End, the westernmost point of mainland England. It’s a beautiful spot, with white sands, deep green sea and amazing sunsets over the Isles (群島) of Scilly, 28 miles away.

The west-facing beach is popular with surfers, with bigger waves and winds often found at the Gwenver end. There’s a beach restaurant with good views of the bay and the sunsets.

The smallest of Isles of Scilly, Bryher is a mile long, half a mile wide — and a natural wilderness of unbelievable scenery. Walk along the narrow sandy roads to the eastern seaboard and you come to two quiet beaches.

Green Bay has views over to the palm trees of Tresco’s Abbey Gardens, and a little further south is Rushy Bay, a beautiful beach facing the deserted island of Samson.

On Bryher, farm shops sell locally grown produce, and they trust you to leave the money in the pot. It’s that kind of place.

1.The best title for this passage is ________.

   A. The Beautiful British Isles                  

B. Secret Beaches on the British Isles

   C. The Most Pleasurable Place in Britain        

D. My Experience of Searching Beaches

2.According to the passage, which of the following is TRUE?

   A. The author is a tourist guide in a tourist agency.

   B. The author likes walking on a rainy cliff-top most.

   C. The author wrote the article to advertise for the beaches.

   D. The author loves beaches that are not known to most people.

3.Which of the following maps can correctly describe the geography position?

   (LE=Land’s End    SC=Sennen Cove        IS=the Isles of Scilly)

4.In the author’s view, farmers on Bryher are ________.

A. sincere            B. selfish        C. courageous     D. mean

 

查看答案和解析>>

同步練習(xí)冊答案