51、(1分)

　　 Everyone knows what a needle is. Of course there are needles and needles, Needles for sewing machines, needles for injection(注射), you name it. But few people think of the wonder a needle works in the hands of those who practice acupuncture(针刺疗法).

　　 During the past ten years of so, I have been suffering from terrible headache. It seems to be getting from bad to worse these days . Last night I got a sudden pain in my head. It was so terrible that I could hardly bear(忍受)it. Although I swallowed all kinds of pain-killers(止痛药), I didn’t feel any better, It seemed that there was nothing I could do but phone for a doctor.

　　 One of our neighbours happened to be with us. He was not a doctor, but he timidly(胆怯地) offered his help, saying “Do you mind if I tried acupuncture on you? These needles may possibly do you some good.” I agreed. In a moment, he had taken out a few needles from his purse. Without a moment’s delay, he fixed a few needles into the skin on my head here and there, Before long, I felt thoroughly relieved(缓解疼痛).

　　 Just then, the doctor sped through my house and said, “Where is our patient?”

　　 “Sorry, Doctor, You are too late, It’s killed!” I answered in delight.

　　 It’s miracle , isn’t it?

5. The best title for this selection would be ______.

　 A. The Sun and the Tides　　　　　　　　　　　 B. Discoveries in Biology

　 C. A scientific Study　　　　　　　　　　　　 D. A Living Clock

4. The crab’s colour-changing ability was probably developed ______.

　 A. in the process of evolution (进化)　　　　 B. over millions of years

　 C. by the work of biologists　　　　　　　 D. both A and B

3. When the fiddler crabs were kept in the dark , they ______.

　 A. did not change colour　　　　　　 B. changed colour more quickly

　 C. changed colour more slowly　　　　 D. changed colour on the same timetable

2. The crab’s changing colour ______.

　 A. tells the crab what time it is　　　　 B. protects the crab from the sunlight and enemies

　 C. keeps the crab warm　　　　　　　 D. is of no real use

1. The fiddler crab is like a clock because it changes colour ______.

　 A in a regular 24-hour rhythm　　　　　　 B. in answer to the sun’s rays

　 C. at low tide　　　　　　　　　　　　　　 D. every fifty minutes

50、(1分)

　　 The fiddler crab (蟹) is a living clock. It indicates(=shows) the time of day by the colour of its skin, which is dark by day and pale by night. The crab’s changing colour follows a regular twenty-four hour plan that exactly matches the daily rhythm (节奏) of the sun.

　　 Does the crab actually keep time, or does its skin simply answer to the sun’s rays, changing colour according to the amount of light strikes it? To find out, biologists kept crabs in a dark room for two months. Even without daylight, the crab’s skin colour continued to change exactly on time.

　　 This characteristic (特性) probably developed gradually in answer to the daily rising and setting of the sun, to help protect the crab from sunlight and enemies. After millions of years it has become completely regulated (受控制) inside the living body of the crab.

　　 The biologists noticed that once each day the colour of the fiddler crab is especially dark, and that each day this happens fifty minutes later than on the day before. From this they discovered that each crab follows not only the rhythm of the sun but also that of the tides (潮水). The crab’s period of greatest darkening is exactly the time of low tide on the beach where it was cought!

5. What did Doctor Edward Lane invent?

　 A. A cheap process of developing film at home.

　 B. A new kind of film.

　 C. An automatic printer.

　 D. An ‘instant camera’ that develops its own film.

4. According to the speaker why is Matthew Bradey remembered today?

　 A. He was a soldier.　　　　　　　　　 B. He took war photographs.

　 C. He painted portraits.　　　　　　　　 D. He designed a portable camera.

3. What does the speaker regard as the official date of beginning of photography?

　 A. 1727　　　　　 B. 1826　　　　　　 C. 1839　　　　　　 D. 1870