首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Despite increased airport security since September 11th, 2001, the technology to scan both passengers and baggage for weapons an
Despite increased airport security since September 11th, 2001, the technology to scan both passengers and baggage for weapons an
admin
2019-05-30
23
问题
Despite increased airport security since September 11th, 2001, the technology to scan both passengers and baggage for weapons and bombs remains largely unchanged. Travellers walk through metal detectors and carry-on bags pass through x-ray machines that superimpose colour-coded highlights, but do little else. Checked-in luggage is screened by "computed tomography", which peers inside a suitcase rather like a CAT scan of a brain. These systems can alert an operator to something suspicious, but they cannot tell what it is.
More sophisticated screening technologies are emerging,
albeit
slowly. There are three main approaches: enhanced x-rays to spot hidden objects, sensor technology to sniff dangerous chemicals, and radio frequencies that can identify liquids and solids.
A number of manufacturers are using "reflective" or "backscatter" x-rays that can be calibrated to see objects through clothing. They can spot things that a metal detector may not, such as a ceramic knife or plastic explosives. But some people think they can reveal too much. In America, civil-liberties groups have stalled the introduction of such equipment, arguing that it is too intrusive. To protect travellers ’modesty, filters have been created to blur genital areas.
Machines that can detect minute traces of explosive are also being tested. Passengers walk through a machine that blows a burst of air, intended to dislodge molecules of substances on a person’s body and clothes. The air is sucked into a filter, which instantaneously analyses it to see whether it includes any suspect substances. The process can work for baggage as well. It is a vast improvement on today’s method, whereby carry-on items are occasionally swabbed and screened for traces of explosives. Because this is a manual operation, only a small share of bags are examined this way.
The most radical of the new approaches uses "quadrupole resonance technology". This involves bombarding an object with radio waves. By reading the returning signals, the machines can identify the molecular structure of the materials it contains. Since every compound—solid, liquid or gas—creates a unique frequency, it can be read like a fingerprint. The system can be used to look for drugs as well as explosives.
For these technologies to make the jump from development labs and small trials to full deployment at airports they must be available at a price that airports are prepared to pay. They must also be easy to use, take up little space and provide quick results, says Chris Yates, a security expert with Jane’s Airport Review. Norman Shanks, an airport security expert, says adding the new technologies costs around $100,000 per machine; he expects the systems to be rolled out commercially over the next 12 months. They might close off one route to destroying an airliner, but a cruel certainty is that terrorists will try to find others.
What is the relationship between the 2nd paragraph and the 3rd, 4th and 5th paragraphs ?
选项
A、A generalization is made in paragraph 2 and then elaborated in paragraph 3,4 and 5.
B、More sophisticated screening technologies are mentioned in paragraph 2 and 3 and then examples are provided in paragraph 4 and 5.
C、Specific evidence is provided in paragraph 1, 2 and 3 and then a conclusion is drawn in paragraph 4.
D、Three main approaches are advanced in paragraph 2,3 and then their functions are detailed in paragraph 4 and 5.
答案
A
解析
本题属于中心主旨题型,测试考生对原文的整体把握和理解能力。原文的第二段是全文的中心主旨段落,指出更高级检测技术的三种主要方法。原文第三、四、五段分别对第二段所提到的三种方式进行了具体的阐述和说明。由此可以推断本题的正确选项是A。考生在阅读时要注意对原文整体结构的把握,尤其要搞清楚段落之间的关系。
转载请注明原文地址:https://kaotiyun.com/show/3GnZ777K
0
考研英语一
相关试题推荐
Nonverbalcommunicationisgreatlyimportant:inanyinteractionwithothers;itsimportanceismultipliedacrosscultures.This
ThereisgrowinginterestinEastJapanRailwayCo.ltd.,oneofthesixcompanies,createdoutoftheprivatizednationalrailw
LatinAmerica—aplacelongassociatedwithfinancialdisaster—hasremainedimprobablycalm,whiletheripplesofAmerica’ssubpr
InatimeoflowacademicachievementbychildrenintheUnitedStates,manyAmericansareturningtoJapan,acountryofhigha
Forhundredsofmillionsofyears,turtles(海龟)havestruggledoutoftheseatolaytheireggsonsandybeaches,longbeforethe
Forhundredsofmillionsofyears,turtles(海龟)havestruggledoutoftheseatolaytheireggsonsandybeaches,longbeforethe
Ifyouknowexactlywhatyouwant,thebestroutetoajobistogetspecializedtraining.Arecentsurveyshowsthatcompaniesl
MuchofcontinentalEuropeisinpoorshape.True,theaggregatewealthofpeopleislittlechangedandthesocialcapitalinmu
Weallknow(orshouldknow)bynowthatthecarbondioxideweproducewhenweburnfossilfuelsandcutdownforestsisthepla
Weallknow(orshouldknow)bynowthatthecarbondioxideweproducewhenweburnfossilfuelsandcutdownforestsisthepla
随机试题
公共关系意识的核心是()
A.外邪侵袭B.湿邪困脾C.脾肾阳虚D.脾胃湿热头面先肿,继而波及全身,小便短少,发热恶风者多因
以下哪项不属急性化脓性骨髓炎临床表现
当事人对裁决不服的,可以在裁决书送达之日起()个月内向人民法院起诉。
某宗房地产预计未来第一年的净收益为16万元,此后每年的净收益会在上一年的基础上增长2%,收益年限可视为无限年,该类房地产的资本转化率为9%,该宗房地产的收益价格为()。
T—DNA可随机插入植物基因组内,导致被插入基因发生突变。用此方法诱导拟南芥产生突变体的过程如下:种植野生型拟南芥,待植株形成花蕾时,将地上部分浸入农杆菌(其中的T—DNA上带有抗除草剂基因)悬浮液中以实现转化。在适宜条件下培养,收获种子(称为T1代)。
=______.
WhowontheWorldCup1994footballgame?WhathappenedattheUnitedNations?Howdidthecriticslikethenewplay?【1】anevent
下面______组设备包括输入设备、输出设备和存储设备。
A、Sheboughttheticketonimpulse.B、Shemeanttoignoretheappointmentwithherprofessor.C、Shewantedtoinviteherprofess
最新回复
(
0
)