人教版高中英语必修五电子课本-第5稿.docx

    人教版高中英语必修五电子课本    按住 Ctrl 键单击鼠标打开配套教学视频名师讲课播放必修 5 Unit 1JOHH SHOW DEFEATS“ KING CHOLERA ”John Snow was a famous doctor in London - so expert, indeed, that he attended Queen Victoria as her personal physicia n. But he became inspired when he thought about helping ordina ry people exposed to cholera. This was the deadly diseas e of its day. Neither its cause nor it s cur e was understood. So many thousands of terrif ied peopl e die d every time there was an outbreak. John Snow wanted to fac ethe challenge and solve thi s problem . He knew that cholera would never be contr olle d unti l its cause was found.He became intereste d in two theories tha t possibl y explained how cholera killed people. The firs t suggested that cholera multiplie d in the air. A cloud of dangerous gas floate d around unt il i t foun d its victims. The second suggested that peopleabsorbed this disease int o thei r bodies withtheir meals. From the stomach the disease quickly attacked the body and soon the affected person died.John Snow suspected that the second theor y was correct but he needed evidence. So when another outbreak hit London in 1854, he was read y to begin his en quir y. As the disease spread quickl y through poor neighbourhoods, he began to gather informatio n. In two particu lar streets , the cholera outbreak was so severe thatmore than 500 people died in ten days. He was determined to find out why.Firs t he marked on a map the exact places where allthe dead people had liv ed. This gave him a valuable clue about th e cause o f the disease. Many of the deaths were near the water pump in Broad Stree t (especially numbers 16, 37, 38 an d 40). He also noticed that some houses (such as 20 and21 Broad Street and 8and 9 Cambridge Street) had had no deaths . He had not foresee n this, so he made furth er investigatio ns. He discovered that these people worked in the pub at 7 Cambridge Street . They had been given free beer and so had not drunk the water from th e pump. It seemed that the water was to blame.Next, John Snow looked into the source of the water fo r these two streets . He found that it came from the river pollute d by the dir ty water from London. He imm ediatel y told the astonishe d people in Broad Stree t to remove the handl e from the pump so tha t it c ould not be used . Soon afterwards the disease slowed down. He had shown that cholera was spread by germs and no t in a cloud of gas. I n another par t of London, he found supporti ng evidence from two other deaths tha t were linke d to the Broad Street outbreak . A woman, who had moved away fr om Broad Stree t, liked th e water from the pump so much that she had i t delivered to her house every day. Both she and her daughte r died o f cholera afte r drinking the water . With thi s extra evidenc e John Snow was able to announce with certai nt y that polluted wate r carrie d the virus . To prevent thi s from happening again , John Snow suggested tha t the source o f all th e water supplie s be examined. The wate r companies were instruct ed not to expose people to polluted wate r any more . Finall y "King Cholera " was defeated .COPERNICUS ’ REVOLUTIONRRY THEORYNicolaus Copernicu s was frightene d and hismind was confused. Although he had tried t o ignore them , al l his mathematical calculatio ns led t o th e same conclusio n: that th e eart h was not the centr e of th e solar system . Only if you put the sun there did the movements o f the other planets i n th e sky make sense. Ye t he couldnot tel l anyone about his theory as the powerful Christian Church would have pun ishe d him for even suggesting such an idea . They believed God had made the world and fo r that reaso n the earth was specia l and must be the centre of the solar system.The problem arose because astronomers had noticed that some planet s in thesky seemed to stop, move backward and the n go forwar d in a loop . Others appeared brighte r at times and less bright at others. This was very strang e i f th e earthwas the centr e o f the sola r system and all planets went round it.Copernicu s had though t lon g and hard about thes e problems and tried to findan answer . He had collected observations of the stars and used all hismathematic al knowledge to explai n them . But only hi s new theor y could do that.So between1510 and 1514 he worked on it , gradually improvin g hi s theor y until he felt it was complete.In 1514 he showed i t privatel y to his friends. The changes he made t o the old theor y were revolutionar y. He placed a fixe d sun at the centre of th e solar system wit h th e planets going round it and only the moon still going roundthe earth. Healso suggested tha t th e earth was spinning as i t went round the sun and this expl aine d changes in the movement of the planets and in the brightnes。