The fiddler crab (蟹) is a living clock. It 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 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 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 caught!
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
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
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
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
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
Shu Pulong has helped at least 1000 people bitten (咬) by snakes. “It was seeing people with snake bites (伤口) that led me to this career,” he said.
In 1963, after his army service, Shu entered a medical school and later became a doctor of Chinese medicine. As part of his studies he had to work in the mountains. There he often heard of people who had their arms and legs cut off after a snake bite in order to save their lives.
“I was greatly upset by the story of an old farmer I met. It was a very hot afternoon. The old man was pulling grass in his fields when he felt a pain in his left hand. He at once realized he had been bitten by a poisonous snake. In no time he wrapped a cloth tightly around his arm to stop the poison spreading to his heart. Rushing home he shouted ‘Bring me the knife!’ Minutes later the man lost his arm forever.”
“The sad story touched me so much that I decided to devote myself to helping people bitten by snakes,” Shu said.
1.The best headline (标题) for this newspaper article is ______ .
A. Astonishing Medicine B. Farmer Loses Arm
C. Dangerous Bites D. Snake Doctor
2.The farmer lost his arm because______.
A. the cloth was wrapped too tightly B. he cut it off to save his life
C. Shu wasn’t there to help him D. he was alone in the fields
3.She decided to devote himself to snake medicine because______.
A. he wanted to save people’s arms and legs B. he had studied it at a medical school
C. he had seen snakes biting people D. his army service had finished
4.Why did Shu go into the mountains? ______
A. He wanted to study snake bites . B. He wanted to help the farmers .
C.He was being trained to be a doctor . D. He was expected to serve in the army .
5.Which of the following words can take the place of the word career in the first paragraph(段)? ______
A. conclusion B. story C. incident D. job
Around 5:30 p.m., I was on the bus one day and everybody on the bus was quiet. People had just 36 from work, students had just finished their 37 class and everybody was a little 38 from a long day. It wasn't a particularly good day for me as I was feeling quite tired too. I was just looking outside of the 39 without any specific thought in my mind. It was the same 40 I had seen many times before, people hurrying home.
In front of me, there was a guy sitting in the seat who didn't look too clean. 41 he was looking out of the window, the guy suddenly 42 to me and pointed at something outside. "Hey, look." He had a big smile on his face. I turned to the 43 he was pointing to and there it was ---- the beautiful Catalina mountains burning with a beautiful 44 . The mountains were coated with bright pink light and shadows. He turned to other people on the bus and told them to look at the mountains. He 45
" Wow" and " It's so beautiful" again and again. Everybody on the bus 46 the views indeed.
The 47 view also helped me to 48 my long tiring day with a good feeling in my heart. But, more 49 , I was so inspired to see that this man wanted to 50 the beautiful view with everybody on the bus, total strangers. His 51 act made me accidentally find something that I had lost which I didn't even know I had lost. He made me 52 that I had lost the feelings and the excitement I 53 have everyday. In my daily life, many things had 54 their color and movement. But he 55 me that things are still there ---- they never get lost.
1.A. gone by B. got off C. given up D. taken up
2.A morning B. important C. last D. boring
3.A. excited B. tired C. puzzled D. disappointed
4.A. window B. classroom C. mountain D. city
5.A. people B. bus C. trouble D. view
6. A. So B. Once C. As D. If
7.A. referred B. attended C. turned D. objected
8.A. finger B. driver C. direction D. sky
9.A. sunset . B. memory C. sunrise D. journey
10. A. wrote B. followed C. discussed D. repeated
11.A. enjoyed B. impressed C. described D. recorded
12. A. amazing B. full C. same D. simple
13. A. save B. hate C. challenge D. end
14. A. fortunately B. naturally C. beautifully D. importantly
15. A. share B. connect C. compare D. comment
16. A. final B. kind C. violent D. direct
17.A. decide B. believe C. realize D. learn
18. A. used to B. was used to C. got used to D. used
19.A. increased B. showed C. faded D. lost
20. A. warned B. reminded C. advised D. persuaded
He is the only man ______ I can find for the work.
A. as B. whose C. that D. which
Tom said the project would be finished by November, ______personally I doubt very much.
A. it B. that C. when D. which
With all the family members ______ on vacation without him, the boy felt extremely lonely and afraid.
A. to have gone B. going C. had gone D. gone
