填空题

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, (36) have reported well over 100 (37) that could have been caused by electromagnetic interference. The source of this interference remains (38) , but increasingly, experts are pointing the (39) at portable electronic devices such as portable computers, radio and cassette players and (40) telephones. RTCA, an organization which advises the aviation industry, has (41) that all airlines ban such devices from being used during "critical" (42) of flight, particularly take-off and landing. Some experts have gone further, calling for a (43) ban during all flights. Currently, rules on using these devices are left up to individual airlines. And (44) , given that many passengers want to work during flights. The difficulty is predicting how electromagnetic fields might affect an aircraft’s computers. (45) . 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. (46) .