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The biggest safety threat facing airlines today may not be a terrorist(恐布分子) 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(電磁) interference(干擾). 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 (禁止)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 prediction 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 communication. 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(易受損的)to interference raises the risk that terrorists may use radio systems in order to damage navigation equipment. Another worrying though, is the passenger who can’t hear the instructions to turn off his radio because the music is too loud .

48.What is said about the over 100 aircraft incidents in the past 15 years?

A.They may have taken place during take-off and landing.

B.They may have been caused by the damage to the radio systems.

C.They were suspected to have resulted from electromagnetic interference.

D.They were proved to have been caused by the passengers’ portable computers.

49.Few airlines want to impose(強加)a total ban on their passengers using electronic devices because           

A.they have other effective safety measures to fall back on

B.they don’t believe there is such a danger as radio interference

C.the harmful effect of electromagnetic interference is yet to be proved

D.most passengers refuse to take a plane which bans the use of radio and cassette players

50.Why is it difficult to predict the possible effects of electromagnetic fields on an airplane’s computers?

A.Because experts lack adequate equipment to do such research.

B.Because it is extremely dangerous to conduct such research on an airplane.

C.Because it remains a mystery what wavelengths are liable to be interfered with.

D.Because research scientists have not been able to produce the same effects in labs.

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科目:高中英語 來源: 題型:閱讀理解

A study of English learning problems was carried out among a total of 106 foreign students.It shows that most students considered understanding spokeu English to be their bigges problern on asrival.This was followed by speaking,Writing increased as a problem as students discovered difficulties in writing papers that they were now expected to hand in.Reading remained as a signifioant(顯著的)problem.

The information gsined helped up in determining where special attention should be paid in our course.Although many atudents have chosen to join the course with a reasonnble motivation(動機),we considered it important to note what seemed to encourage inleresl.Neady all the students have experienced some kind of grammar-based English teaching in their own country.To use the sarnc method would be self-defeating because it might reduce motivation,especially if it has failed in the pest.Thereforc a different method may help henause it is different.

Variety of activity was also seen as a way of maintsining(保持)or incressing motivation.Several years ago we had one timetable that operated throughout,but we soon found that both the students and the teachers lost interest by about halfway through the ten weeks.This led up to a majoc re-taink,so finally we hrought it into line with the expressed language needs of the students.

1.What is the text mainly about?

A.Foreign students have more problems.

B.There are many ways to improve English.

C.Tesching should meet students’needs.

D.English learning probles should be studied again.

2.Writing became a bigger problem when foreign students       .

A.had to writs their paers

B.became better at speaking

C.became less interested in reading

D.had fewer problems with listening

3.We may infer from the last lwo paragraphs that           .

A.different teaching methods should be used

B.grammar-hased teaching seems to be encouraging

C.English courses are necessary for foreign students

D.teaching content should be changed halfway

4.The word“it” underlined in the last paragraph refers to“           ”.

A.re-think

B.activity

C.molivation

D.timetable

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