第5部分：补全短文(第46～50题，每题2分，共10分)
下面的短文有5处空白，短文后有6个句子，其中5个取自短文，请根据短文内容将其分别放回原有位置，以恢复文章原貌。
Watching Microcurrents Flow
We can now watch electricity as it flows through even the tiniest circuits. By scanning (扫描) the magnetic field (磁场) generated as electric currents flow through objects (物体), physicists have managed_______(46). The technology will allow manufacturers to scan microchips for faults, as well as revealing microscopic defects in anything from aircraft to banknotes.
Gang Xiao and Ben Schrag at Brown University in Providence, Rhode Island, visualize the current by measuring subtle (细微的) changes in the magnetic field of an object and _______(47).
Their sensor is adapted from an existing piece (现有配件) of technology that is used to measure large magnetic fields in computer hard drives. "We redesigned the magnetic sensor to make it capable of measuring (测量) very weak changes in magnetic fields," says Xiao.
The resulting device is capable of detecting (测定) a current as weak as 10 microamperes, even when the wire is buried deep within a chip, and it shows up features (图案) as small as 40 nanometers across.
At present, engineers looking for defects (缺陷) in a chip have to peel off (剥开) the layers and examine the circuits visually; this is one of the obstacles _______(48). But the new magnetic microscope is sensitive enough to look inside chips and reveal faults such as short circuits, nicks in the wires or electro migration (电迁移) – where a dense area of current picks up surrounding atoms and moves them along. "It is like watching a river flow," explains Xiao.
As well as scanning tiny circuits, the microscope can be used to reveal the internal structure of any object capable of conducting electricity. For example, it could look directly at microscopic cracks in an airplane’s fuselage, _______(49). The technique cannot yet pick up electrical activity in the human brain because the current there is too small, but Xiao doesn't rule it out (排除……的可能性) in the future. "I can never say never," he says.
Although the researchers have only just made the technical details of the microscope public, it is already on sale, (上市) from electronics company Micro Magnetics in Fall River, Massachusetts. It is currently the size of a refrigerator and takes several minutes to scan a circuit, but Xiao and Schrag are working _______(50).
A. to shrink it to the size of a desktop computer and cut the scanning time to 30 seconds
B. to making chips any smaller
C. to take tiny chips we require
D. to picture the progress of the currents
E. converting the information into a color picture showing the density of current at each point
F. faults in the metal strip of a forged banknote or bacteria in a water sample
第6部分：完形填空(第51～65题，每题1分，共15分)
下面的短文有15处空白，请根据短文内容为每处空白确定1个最佳选项。
A Biological Clock
Every living thing has what scientists call a biological clock that controls behavior. The biological clock tells ______ (51) when to form flowers and when the flowers should open. It tells ______ (52) when to leave the protective cocoons and fly away, and it tells animals and human beings when to eat, sleep and wake.
Events outside the plant and animal ______ (53) the actions of some biological clocks. Scientists recently found, for example, that a tiny animal changes the color of its fur ______ (54) the number of hours of daylight. In the short ______ (55) of winter, its fur becomes white. The fur becomes gray brown in color in the longer hours of daylight in summer.
Inner signals control other biological clocks. German scientists found that some kind of internal clock seems to order birds to begin their long migration______ (56) twice each year. Birds ______ (57) flying become restless when it is time for the trip. ______ (58) they become calm again when the time of the flight has ended.
Scientists say they are beginning to learn which ______ (59) of the brain contain biological clocks. An American researcher, Martin Moorhead, said a small group of cells near the front of the brain ______ (60) to control the timing of some of our actions. These ______ (61) tell a person when to ______ (62), when to sleep and when to seek food. Scientists say there probably are other biological clock cells that control other body activities.
Dr. Moorhead is studying ______ (63) our biological clocks affect the way we do our work. For example, most of us have great difficulty if we must often change to different work hours.
______ (64) can take many days for a human body to accept the major change in work hours. Dr.Moorhead said industrial officials should have a better understanding of biological clocks and how they affect workers. He said ______ (65) understanding could cut sickness and accidents at work and would help increase a factory’s production.
51. A. scientists B. humans C. plants D. animals
52. A. insects B. birds C. fish D. snakes
53. A. effect B. affect C. effected D. affected
54. A. because B. for the reason that C because of D. since
55. A. months B. days C. minutes D. weeks
56. A .flight B. fly C. movement D. transportation
57. A. prevented from B. ordered by C. helped by D. intruded on
58. A. and B. but C. therefore D. however
59. A. portions B. parts C. sections D. kinds
60. A. try B. tries C. seem D. seems
61. A. things B. parts C. cells D. actions
62. A. awaken B. woke C. awakening D. wake-up
63. A. how B. why C. where D. what
64. A. We B. It C. They D. You
65. A. so B. with C. such D. if
