第六部分：完形填空

　　阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。

　　More about Alzheimer's Disease

　　Scientists have developed skin tests that may be used in the future to identify people with Alzheimer's disease1 and may ultimately allow physicians to predict ________ (51) is at risk of getting this neurological disorder.

　　The only current means of ________ (52) the disease in a living patient is a long and expensive series of tests that eliminate every other cause of dementia.(痴呆)

　　“ Since Alois Alzheimer described the ________ (53) nearly a century ago，people have been trying to find a way to ________ (54) diagnose it in its early stages2，” said Patricia Grady，acting director3 of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. "This discovery, if ________ (55) , could prove a big step forward in our efforts to deal with and understand the disease. ”

　　Alzheimer's is the single greatest ________ (56) of mental deterioration in older people, affecting between 2. 5 million and 4 million people in the United States ________ (57). The devastating disorder gradually destroys memory and the ability to function，and eventually causes death.6 There is currently no known _______ (58) for the disease.

　　Researches ________ (59) that the skin cells of Alzheimer' s patients have defects that interfere with their ability to regulate the flow of potassium in and out of the cells. The fact that the cell defects are present in the skin suggests that7 Alzheimer's ________ (60) from physiological changes throughout the body，and that dementia may be the first noticeable effect of these changes as the defects ________ (61) the cells in the brain, scientists said.

　　The flow of potassium is especially ________ (62) in cells responsible ________ (63) memory formation8. The scientists also found two other defects that affect the cells' supply of calcium, another critical element.

　　One test developed by researches calls for9 growing skin cells in a laboratory culture and then testing them with an electrical detector to determine if the microscopic tunnels that ________ (64) the flow of potassium are open. Open potassium channels create a unique electrical signature.

　　A spokesman for the Alzheimer's Association said that if the validity of the diagnostic test can be proven it would be an important ________ (65) , but cautioned that other promising tests for Alzheimer's have been disappointing.

　　51. A. what B. one C. it D. who

　　52. A. fighting B. carrying C. transmitting D. diagnosing

　　53. A. answer B. effect C. disease D. study

　　54. A. slowly B. accurately C. newly D. incorrectly

　　55. A. designed B. announced C. confirmed D. reported

　　56. A. cause B. factor C. focus D. exception

　　57. A. finally B. lonely C. yet D. alone

　　58. A. examination B. evidence C. treatment D. fact

　　59. A. discovered B. predicted C. expected D. warned

　　60. A. keeps B. breaks C. results D. translates

　　61. A. affect B. remove C. collect D. form

　　62. A. steady B. natural C. continuous D. critical

　　63. A. at B. out C. for D. of

　　64. A. start B. get C. follow D. govern

　　65. A. chance B. concept C. development D. decision

　　答案：

　　51-55：DDCBC

　　56-60：CDCAC

　　61-65：ADCDC