A breathtaking trick potentially left over from our ancestors might be found in us — the ability to sense oxygen through our skin.
Amphibians, animals such as frogs that can live both on land and in water, have long been known to be capable of breathing through their skin. In fact, the first known lungless frog that breathes only through its skin was discovered recently in the rivers of Borneo.
Now the same oxygen sensors found in frog skins and in the lungs of mammals (哺乳动物) have unexpectedly been discovered in the skin of mice.
“No one had ever looked,” explained Randall Johnson, a biologist researcher.
Mice and frogs are quite distant relatives, so the fact they have these molecules (分子) in common in their skin suggests they might well be found in the skin of other mammals, such as humans.
“We have no reason to think that they are not in the skin of people too,” Johnson said.   These molecules not only detect oxygen, but help increase levels of vital red blood cells, which carry oxygen around the body. Normal mice breathing in air that is 10 percent oxygen—a dangerously low level similar to conditions at the top of Mount Everest, and about half that of air at sea level. However, mice that had the oxygen sensor HIF-1a genetically removed from their skin failed to produce this hormone (荷尔蒙) even after hours of such low oxygen.
These findings, if they hold true in humans, suggest one could raise the level of oxygen circulating inside the body. This could help treat lung diseases and disorders such as anemia (贫血症) without injecting drugs, which make up a multibillion-dollar market, Johnson said.
Athletes also often try to get more oxygen delivered to their muscles in order to improve their performance. They often do this by training at high altitudes or in low-oxygen tents. The new study suggests they might want to expose their skin as well as breathing in low-oxygen air to improve their performance. “It’s hard to say what exactly might be done, however—there’s a lot we don’t know yet,” Johnson explained.
The scientists detailed their findings in the April 18 issue of the journal Cell.
49. Which of the following statements is TRUE according to the passage?
A. Johnson believes that Oxygen sensors also exist in human skin.
B. People have to surf the Internet to read detailed findings.
C. It has been proved that these findings help treat lung diseases.
D. It has long been expected oxygen sensors exist in mice’s skin. 
50. One of the functions of the molecules mentioned above is _______.
A. carrying oxygen around the body                   B. improving athletes’ performance
C. detecting oxygen                                          D. increasing level of oxygen
51. What is Johnson’s attitude to the application of the findings to the athletes’ training?
A. Negative                  B. Doubting                  C. Positive             D. Hesitating
52. The best title of the passage may be _______.
A. Great Findings Benefits Athletes A Lot
B. Frogs And Mice Are Distant Relatives
C. First Known Animal Breathes Through Skin
D. Humans Might Sense Oxygen Through Skin

阅读下面短文，掌握其大意，然后从短文后所给各题的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。

People do not analyse every problem they meet. Sometimes they try to remember a solution from the last time they had a 36 problem. They often accept the opinion or ideas of other people. Other times they begin to act without 37  ; they try to find a solution by trial and error. However, when all of these methods 38  , the person with a problem has to start analyzing . There are six 39 in analysing a problem.

40 ,  the person must recognize that there is a problem. For example, Sam’s bicycle is broken, and he cannot ride it to class as he usually does. Sam must 41 that there is a problem with his bicycle.

Next the person must 42 the problem. Before Sam can repair his bicycle, he must know why it does not work. For example, he must 43 the parts that are wrong.

Now the person must look for 44 that will make the problem clearer and lead to 45 solutions. For example, suppose Sam 46 that his bike does not work because there is something wrong with the brakes. 47   , he can look in his bicycle repair book and read about brakes, talk to his friends at the bike shop, or look at his brakes carefully.

After 48 the problem, the person should have several suggestions for a possible solution. Take Sam as an example 49   , his suggestions might be: tighten or loosen the brakes; buy new brakes and change the old ones.

In the end, one 50 seems to be the solution to the problem. Sometimes the 51 idea comes quite 52 because the thinker suddenly sees something in a 53 way. Sam, for example, suddenly sees there is a piece of chewing gum stuck to a brake. He immediately hits on the solution to his problem: he must 54 the brake.

Finally the solution is 55   . Sam does it and finds his bicycle works perfectly. In short he has solved the problem. 

A. serious           B. usual                 similar                    D. common

A. practice     B. thinking            understanding        D. help

A. fail                B. work                 change                    D. develop

A. ways           B. conditions         stages                     D. orders

A. First              B. Usually             In general            D. Most importantly

A. explain         B. prove                show                   D. see

A. judge          B. find                  describe            D. face

A. check           B. determine        correct                      D. recover

A. answers        B. skills              C. explanation         D. information

A. possible      B. exact           C. real                 D. special

A. hopes         B. argues            C. decides               D. suggests

A. In other wordsB. Once in a while C. First of all         D. At this time

A. discussing    B. settling down    C. comparing with      D. studying

A. secondly     B. again             C. also                   D. alone

A. suggestion  B. conclusion         C. decision             D. discovery

A. next          B. clear            C. final                  D. new

A. unexpectedly B. late              C. clearly               D. often

A. simple          B. different         C. quick               D. sudden

A. clean            B. separate          C. loosen               D. remove

A. recorded           B. completed        C. tested                       D. accepted 

________, it began to rain unexpectedly.

A. While cleaning the machine

B. To clean the machine

C. He was cleaning the machine

D. While he was cleaning the machine

Now I’d like to talk to you about your final exam. The exam will be held next Thursday, the last day of the exam week. Remember to bring two or three pens in case you run out of ink. And unlike the midterm exam, this test will not include multiple-choice questions; it will consist (由…组成) entirely of essays (文章). You’ll have to answer three of the five essay questions. The exam will be comprehensive (理解性的), which means you’ll be responsible (负责) for all of the subject matters we covered in class this term. I would suggest you review your midterm exam as well as textbooks and your class notes. The research project will count as 20 percent and the midterm exam 30 percent. I’ll be in my office almost all day next Tuesday. If you run into any problems, please drop in. Gook luck to you and I’ll see you on Tuesday.

1 The final exam take place on a ____ .

         A. Tuesday        B. Wednesday C. Thursday      D. Friday

2 What will be included in the exam?

         A. There will be only multiple-choice questions.

         B. The exam will contain both multiple-choice and essay questions.

         C. The exam will have an oral and written section.

         D. There will be only essay questions.

3 Why does the teacher call the exam comprehensive?

         A. Because it will be easy to understand.

         B. Because it will cover topics from a variety (多种多样) of subjects.

         C. Because students will be tested on all the material discussed in class.

         D. Because students must complete all parts of it.

4 The underlined phrase run into probably means ____ .

         A. meet somebody unexpectedly    B. go into

         C. come across (偶然遇见)    D. come up against something with force

How “Kangaroo” Became an Animal’s Name

Early in the 18th century, Captain Cook, a famous explorer of Australia, unexpectedly caught sight of an unusual animal during his first visit to Australia. The animal had a large mouth-like head and jumped along on its large legs. To his surprise, the unusual animal carried it’s young in a special pocket of flesh. Captain Cook pointed to the animal which was eating grass in the distance and asked his native guide what the animal was referred to. The guide seemed not to know what he was pointing at and finally said Kang-a-roo, which Cook carefully wrote down as the animal’s name in his word book. The Europeans who later got to Australia were anxious to see the unusual animal “Kang-a-roo”, but their requests met with puzzled looks of the native people. Before long they got to discover that the native guide who made the answer to Cook’s question really meant, “I don’t know what you are pointing at.” Funny enough, the name “Kang-a-roo” stuck and it is still in use today.

60. Which of the following sentences best expresses the main idea?

   A. Captain Cook’s guide had a sense of humour.

   B. Native Australians could speak English in Cook’s time.

   C. Some words have rather funny origins.

   D. Captain Cook was a lover of wild animals.

61. The main use for the animal’s flesh pocket is to_______.

   A. keep food                       B. carry its babies

   C. a long distance                D. store food and water

62. When the native guide said “Kang-a-roo” he really meant_______

   A. “Ah, it is a special kind of animals.”      

   B. “I wonder what you have said.”

   C. “I have no idea of what you are pointing at.”

   D. “What do you mean by pointing at that animal?”

63. The writer indirectly expresses that early in the 18th century_______

A. the native Australians and the Europeans explorers were not friendly to each other.

B. a common language was needed by the Europeans to communicate with the   native in Australia.

C. a great many Europeans showed great interest in Australia.

D. a war against the European invaders was a break out