Ⅱ.完形填空
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 past 15 years，__1__have reported well over 100__2__that could have been caused by electromagnetic interference(干扰). The__3__of this interference remains unconfirmed，__4__increasingly, experts are pointing the blame at portable electronic devices such as portable computers, radios and cassette players and mobile telephones.
RTCA, an organization which__5__the aviation industry, has recommended that__6__airlines ban such electronic devices from being used__7__“critical”stages of flight，__8__takeoff and landing. Some experts have gone further，__9__for a total ban during all flights. Currently, rules on using these devices are__10__up to individual airlines. And although some airlines prohibit(禁止)passengers from__11__such equipment during takeoff and landing, most are reluctant to enforce a total ban. Many passengers want to work during flights.
The__12__is predicting how electromagnetic fields__13__affect an aircraft's computers. Experts__14__that portable devices emit radiation, which affects those wavelengths which__15__use for navigation and communication. But, they have not been able to__16__these effects in a laboratory; they have no__17__of knowing whether the interference might be__18__or not.
The fact that aircraft may be vulnerable(易受攻击)to interference__19__the risk that terrorist may use radio system in order to__20__navigation equipment.
1.A.drivers B.pilots
C.engineers D.conductors
答案：B 文章第一句已表明：当今航空公司面对的最大的安全威胁不是持枪的恐怖分子，而是手提电脑。所以对飞机上的这种事情最了解的应是飞行员，而不是A、C、D的那些人。
2.A.actions B.events
C.matters D.incidents
答案：D 此处指飞机上发生的这类事情。本题同样考查了词义辨析。incident指“较小的事件，插曲，小故事”，action是“(采取的)行动”之意，event是“大事件”，matter指“问题，事情，或麻烦事”等，均不合适。
3.A.reason B.effect
C.source D.story
答案：C 根据下句话得知“手提电脑，移动电话”等这些电子装置应是“干扰源”，而不是受干扰的结果，受干扰的应当是飞机。reason不合适是因为reason接for而不接of，表示“……的原因”。
4.A.and B.for
C.but D.so
答案：C “没有确认”(unconfirmed)与“在增加”(increasing)中间应是转折关系，不是递进、因果关系，所以不选A、B、D。
5.A.advises B.persuades
C.ensures D.warns
答案：A 因为下文用了recommend(劝告)一词，所以这个组织应该是向航空工业提建议的一个组织，这样才前后一致。
