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  3. The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable computer in bus

The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable computer in bus

admin2013-01-05  18
问题     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 that well over 100 incidents could have been caused by electromagnetic interference. The source of this interference remains unconfirmed, but increasingly, experts are pointing the blame at portable electronic device 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. 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 enforce a total ban, given that many passengers want to work during flights.
    The difficulty is predicting how electromagnetic fields might affect an aircraft’s computers. Experts know that portable device emit radiation which affects those wavelengths which aircraft use for navigation and communicatioa But, because they have not been able to reproduce these effects in a laboratory, they have no way of knowing whether the interference might be dangerous or not.
    The fact that aircraft may be vulnerable (易受损的) to interference raises the risk that terrorists may use radio systems in order to damage navigation equipment. As worrying, though, is the passenger who can’t hear the instructions to turn off his radio because the music’s too loud. (275 words)
Why is it difficult to predict the possible effects of electromagnetic fields on an airplane’s computers?
选项 A、Because it is extremely dangerous to conduct such research on an airplane.
B、Because it remains a mystery what wavelengths are liable to be interfered with.
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.
答案C
解析 本题属于细节归纳题。根据题干的问题，可确定本题指向第三段要点：困难之一，难以预测电磁场怎样影响导航电脑；困难之二，无法通过实验室模拟，故无从确切知道这种干扰是否危险。因此C是正确答案。
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