The biggest safety threat（威脅）facing airlines today may not be a man with a gun ,but the man with portable（便攜式）computer in business class .In the past 15 years ,pilots have reported about over 100 incidents that could have been caused by electro-magnetic interference(電磁干擾) .The source of this interference remain unclear ,but increasingly ,experts are pointing the blame at portable electronic devices（設(shè)備）such as portable computers ,radio and mobile telephones .
RTCA ,an organization which advises the aviation industry ,has suggested that all airlines ban, such devices from being used during “key” stages of flight ,particularly take-off and landing .Some experts have gone further ,calling for a total ban during all flights .Nowadays ,rules on using these devices are left up to airlines. And although some airlines ban passengers from using such equipment during take-off and landing ,most are not willing to exercise a total ban ,if many passengers want to work during flights .
The difficulty is understanding how electromagnetic fields might affect an aircraft’s computers .Experts know that portable devices give off radiation which affects those wave lengths which aircraft uses for 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 in trouble because of the interference raises the danger
that some people may use radio systems in order to damage navigation（導(dǎo)航）equipment .As worrying ,though ,is the passenger who can’t hear the instruction to turn off his radio because the music is too loud .
小題1:.
.What is said about over 100 aircraft incidents in the past 15 years ?
A They may have taken place during take-off and landing .
B They have been caused by the damage to the radio systems .
C They were said to have resulted from electro-magnetic interference .
D They were caused by the passengers’ portable computers .
小題2:.
. Few airlines want to refuse a total ban on their passengers because ____ .
A they have other effective safety measures to fall back on
B they don’t believe there is such a danger as radio interfe
rence
C the effect of electromagnetic interference is yet to be proved
D most passengers refuse to take a plane which bans the use of radio
小題3:.
. Why is it difficult to see the effects of electromagnetic fields on computers ?
A Experts lack proper equipment to such research .
B It is dangerous to carry out such research on an airplane .
C It remains a question what wave lengths are to be interfered with .
D Scientists are not able to produce the same effects in laboratory .
小題4:.
It can be inferred from the passage that the author ___ .
A hasn’t formed his own opinion on this problem
B has fully understood the danger of electromagnetic interference
C regards it is as unreasonable to exercise a total ban during fligh
t
D is in favor of banning passengers’ use of electronic devices
各地期末復(fù)習(xí)特訓(xùn)卷系列答案
小博士期末闖關(guān)100分系列答案
名校名師培優(yōu)作業(yè)本加核心試卷系列答案
n with LD are less 37 and often rejected by their peers. Teachers and other adults also may 38 to have negative views of them. Such social rejection(排斥)can result in 39 of self-esteem and feelings of loneliness, which, 40 may lead to psychological difficulties such as anxiety and depression.
slightly
o on to 40 , maybe even be president someday, and she wanted
to prepare them for that day．
I just don’t see 49 ．”
you 52 ．
ou in college at such a young, 40 age ?”I asked. “I always dreamed of having a 41 experience and now I’m getting 42 !” she told me.
. learned D. debated
pinions
m