1.The passage is mainly about -----.

1.The passage is mainly about _____.A.the defects of electronic devicesB.a possible cause of aircraft crashesC.a new regulation for all airlinesD.effective safety measures for air flight2.What is said about the over 100 aircraft incidents in the past 15 years?A.They were suspected to have resulted from electromagnetic interference.B.They may have been caused by the damage to the radio systems.C.They may have taken place during take-off and landing.D.They were proved to have been caused by the passengers' portable computers.3.Few airlines want to impose a total ban on their passengers using electronic devices because _____A.they don't believe there is such a danger as radio interferenceB.the harmful effect of electromagnetic interference is yet to be provedC.they have other effective safety measures to fall back on D.most passengers refuse to take a plane which bans the use of radio and cassette players4.Why is it difficult to predict the possible effects of electromagnetic fields on an airplane's computers?A.Because it remains a mystery what wavelengths are liable to be interfered with.B.Because experts lack adequate equipment to do such research.C.Because it is extremely dangerous to conduct such research on an airplane.D.Because research scientists have not been able to produce the same effects in labs.5.It can be inferred from the passage that the author _____.A.is in favor of prohibiting passengers' use of electronic devices completelyB.regards it as unreasonable to exercise a total ban during flightC.hasn't formed his own opinion on this problemD.has overestimated the danger of electromagnetic interference