Flying over a desert area in an airplane, two scientists looked down with trained eyes at trees and bushes. After an hour’s flight one of the scientists wrote in his book, “Look here for probable metal. ” Scientists in another airplane, flying over a mountain area, sent a message to other scientists on the ground, “Gold possible. ” Walking across hilly ground, four scientists reported, “This ground should be searched for metal. ” From an airplane over a hilly wasteland a scientist sent back by radio one word, “Uranium. ”

None of the scientists had X-ray eyes:  They had no magic power of looking down below the earth’s surface. They were merely putting to use one of the newest methods of locating minerals in the ground. . . trees and plants as signs that certain minerals may lie beneath the ground on which the trees and plants are growing.

This newest method of searching for minerals is based on the fact that minerals deep in the earth may affect the kind of bushes and trees that grow in the surface.

At Watson Bar Greek, a brook(小溪) six thousand feet high in the mountains of British Columbia, Canada, a mineral search group gathered bags of tree seeds. Boxes were filled with small branches from the trees. Roots were dug out and put into boxes. Each bag and box was carefully marked. In a scientific laboratory the parts of the forest trees were burned to ashes and tested. Each small part was examined to learn whether there were minerals in it.

Study of the roots, branches, and seeds showed no silver. But there were small amounts of gold in the roots and a little less gold in the branches and seeds. The seeds growing nearest to the tree trunks had more gold than those growing on the ends of the branches.

71. Scientists were flying over a desert or a hilly wasteland or a mountain area in order to search for_______in the ground.

A. gold                                              B. silver

C. metals                                           D. minerals

72. The scientists were searching for minerals by using_______ .

A. X-ray                                            B. magic power

C. a special instrument                 D. trained eyes

73. Which of the following is NOT mentioned as part of a tree that can help find minerals?

A. Leaves.                                        B. Roots.

C. Branches.                                      D. Seeds.

74. The study of trees, branches and roots shows that_______ .

A. there were larger amounts of gold in the branches than in the seeds

B. there were smaller amounts of gold in the roots than in the branches

C. there were less amounts of gold in the seeds growing on the ends of branches than seeds growing nearest to the tree trunks

D. there was more gold in the branches than in the roots

75. Which is the best title suggested below?

A. Scientists Searching for Metals with Special Power

B. New Methods of Searching for Minerals

C. Gold Could Be Found by Trees and Plants

D. A New Method of Searching for Minerals—Using Trees and Plants

The scientists were trying to look for all possible _______ as to where this species came from.

A．signals            B．marks            C．clues             D．spots

 

Look closely at ,your hands-are they clean? It doesn't matter how many times you was  your hands. They're still crowded with microbes, which are also called "germs" or "bacteria". Microbes are everywhere. But don't worry-most microbes don't harm you. and many actually help you stay alive.

Now,  scientists say the microbes that live on our hands could be used in a surprising way: fighting crime.

When police visit the scene of a crime, they often look for fingerprints to try to identifythe criminal.  But according to a recent study, investigators could even use microbes to help break a criminal case.

Every person has his or her own set of microbes that live on their hands, according to scientists at,the University of:Colorado. That means the mix of different kinds of microbes on everybody's hand is unique-much like one's fingerprint.

The scientists wanted to know whether this microbe mix could be used as a new kind of fingerprint-especially in a crime scene where fingerprints might be hard to find.  And policemen use forensics such as studying fingerprints to identify the criminal.

"Microbe fingerprints are harder to hide," said Noah Fierer, one of the scientists.

"You can't sterilize(为……杀菌) a surface just by wiping it off. "

His team compared the bacteria on the hands of 273 people with the bacteria found on each person's computer keyboard. For the study, the keyboards had been used only by the people who were being tested. The study showed that the mix of microbes from each per- son's hands matched the mix of microbes on that person's keyboard. The scientists were easily able to tell the 273 people apart-just by looking at their keyboards.

But there are a lot more than 273 criminals. Other scientists wonder whetherthe microbe fingerprint can really be that useful. 

Fierer agrees that scientists have a lot more work to do before the microbe fingerprint will be a useful tool．

1.According to the passage,  microbes on people's hands_____

A．do more harm than good                 B．are easy to get rid of

C．are almost the same                     D．might help find crimes

2.The underlined word "forensics" in Paragraph 5 probably refers to________.

A．the scientific test used by police

B．a new kind of fingerprint

C．a kind of bacteria'in people's hands

D．a kind of newly invented keyboard

3.What did Fierer's team find through the study?

A．They found the criminal among the 237 people.

B．They could tell who had used which computer.

C．Computer keyboards couldn't keep people's microbe fingerprints.

D．People's characters could be identified by the keyboards they used.

4.We can learn from the passage that ______.

A．your microbes may give you away

B．scientists will come to a clear conclusion soon

C．many scientists think microbe fingerprints useless

D．the microbe fingerprint has been used in many cases

5.The main idea of the passage is about_____.

A．the importance of fingerprints             B．how to clean our hands

C．the usefulness of microbes                D．different germs on our hands

 

　 The scientists were waiting to see the problem _____.

　　A. settle　　 B. to settle   C. settled　　D. settling

    A recent announcement by scientists that they have successfully cloned the first human embryo has caused much debate and has shocked many people around the world. On the one hand，some scientists point out that if you clone an embryo，you can produce valuable tissues(组织）and organs that could be used to save human lives. On the other hand，many people，including some scientists, disagree and fear that if mankind interferes with（干涉）nature in this way，they may be on their way to producing a real-life Frankenstein’s monster.

    Cloning is producing an exact copy of a plant or an animal using its cells. The first mammal to be cloned successfully from an adult cell was Dolly the sheep. She was born in 1996 and died in early 2003，at a much younger age than normal. When she was born，many people were angry because they thought cloning would create more disease in the animal world. However，in general the scientists were praised for their wonderful scientific breakthrough.

    The Scottish scientist who created Dolly，Ian Wilmut，is shocked that some scientists are now considering cloning human beings. Although he researches cloning，his intention has never been to create copies of humans. Instead，he thinks research efforts should concentrate on creating new tissues and organs that could eventually be used to cure diseases like cancer. However，some people consider that cloning human embryos with the intention of destroying them shows no respect for human life.

    While cloning human embryos is illegal in many countries，some scientists are already pushing ahead with research so as to deliver a cloned human baby. Severino Antinori，an Italian doctor，is one of the leaders in this kind of research. He has declared that he wants to be the first to clone a human being.

    In China，scientists have focused their efforts on cloning animals，as well as stern cells to be used in medical research. China has succeeded in producing clones of cows and goats，and continues to research ways in which cloning can benefit mankind.

51. Which of the following statements about cloning is TRUE according to the passage?

A. Cloning technology can only be applied to animals.

B. A cloned animal can live longer than a normal one.

C. People all over the world are happy about the birth of Dolly.

D. Cloning can produce valuable tissues and organs to cure human diseases.

52. The reasons why people are anti-cloning include the following EXCEPT that_______.

A. cloning may produce a real-life Frankenstein’s monster

B. cloning might create more disease in the animal world

C. cloning can’t help those who want to clone their dead children

D. cloning human embryos shows no respect for human life

53. Who is in favor of cloning human beings?

A. Ian Wilmut.        B. Severino Antinori.

C. The author.        D. The Chinese scientists.

54. What can be inferred from the last two paragraphs?

A. If we interfere with nature, we will change the world to be what we want.

B. It is impossible to clone babies for women who cannot have ones.

C. Cloning human beings is illegal in many countries，so no scientists want to do so.

D. Whether cloning human embryos is legal or not remains a matter of debate.