更多"In the past,one of the biggest disa"的相关试题:
[填空题]In the past,one of the biggest disadvantages of machines has been their inability to work on a micro-scale. For example,doctors did not have devices allowing them to go inside the human body to (36) health problems or to perform (37) surgery. Repair crews did not have a way of (38) broken pipes located deep within a high-rise (39) building. However, that’s about to change. Advances in computers and biophysics have started a microminiature (超微) (40) that allows scientists to envision—and in some cases actually build— microscopic machines. These devices promise to (41) change the way we live and work.
Micromachines already are making an impact. At Case Western Reserve University in Cleveland,Ohio, research scientists have designed a 4-inch silicon chip that holds 700 tiny (42) motors. At Lucas NovaSensor in Fremont,California,scientists have perfected the world’s first microscopic blood-pressure sensor. Threaded through a person’s blood (43) , the sensor can provide blood pressure readi
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BP is one of Britain’s biggest companies and one of the
world’s largest oil and petrochemicals (石油化工产品) groups.
BP owes
its origin to one man, William Knox D’Arey, who, shortly after the turn of the
twentieth century, invested time, money and labour in the belief that worthwhile
deposits of oil could be found in Persia.
In the company’s first
six decades, its prime focus lay in the Middle East. But from the late 1960s the
centre of gravity shifted westwards, towards the USA and Britain
itself.
However, the BP of today is an international company,
having operations in over 70 countries. Its key strengths are in oil and gas
exploration and production the refining, marketing and supply of petroleum
product (石油产品); and the manufacturing and marketing of chemicals. It supports
all its businesses with high quality research and technology.
The following pages chronicle (记录) the development of the company from its
early days throu
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The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable computer in business class. In the last 15 years, pilots have reported well over 100 incidents that could have been caused by electromagnetic interference. The source of this interference remains unconfirmed, but increasingly, experts are pointing the blame at portable electronic devices such as portable computers, radio and cassette players and mobile telephones.
RTCA, an organization which advises the aviation (航空) industry, has recommended that all airlines ban(禁止)such devices from being used during "critical" stages of flight particularly take- off and landing. Some experts have gone further, calling for a total ban during all flights. (76) Currently, rules on using these devices are left up to individual airlines. And although some airlines prohibit passengers from using such equipment during take- off and landing, most are reluctant to en
A. Because it remains a mystery what wavelengths are liable to be interfered with.
B. Because it is extremely dangerous to conduct such research on an airplane.
C. Because research scientists have not been able to produce the same effects in labs.
D. Because experts lack adequate equipment to do such research.
