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
2019-04-19
68
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/kznZ777K
0
考研英语一
相关试题推荐
InEurope,therehasbeenaseriousdeclineinphysicalactivityoverthepast50years.Adultsaged20-60years【C1】______500kca
InEurope,therehasbeenaseriousdeclineinphysicalactivityoverthepast50years.Adultsaged20-60years【C1】______500kca
Americaisoneofmanycountrieswherethestategivesaleg-uptomembersofcertainracial,ethnic,orothergroups【C1】______h
Americaisoneofmanycountrieswherethestategivesaleg-uptomembersofcertainracial,ethnic,orothergroups【C1】______h
Manypeopleliketotravel.Theproblemisgettingyourpettothe【C1】______.Inrecentyears,transportingpetsonflightshas
Parentsandstudentsarenowrelyinglessontakingoutloansandmoreongrants,scholarshipsandtheirownincomeandsavings,
Prewritingreferstostrategiesyoucanusetogenerateideasbeforestartingthefirstdraftofapaper.Prewritingtechniques
Aperson’shomeisasmuchareflectionofhispersonalityastheclotheshewears,thefoodheeatsandthefriendswithwhomh
People’sfinancialhistoryhasastrongimpactontheirtasteforrisk.LookingatsurveysofAmericanhousehold【C1】______from1
WilltheEuropeanUnionmakeit?Thequestionwouldhavesoundedstrangenotlongago.Noweventheproject’sgreatestcheerlead
随机试题
肝右静脉走行于右叶间裂内,是下面哪一项解剖结构的分界标志
三期梅毒的标志性表现是
男性,27岁。发热、咳嗽月余,伴身体乏力、消瘦,近1周来咯血,体温波动在37.5~38℃,X线胸片示右肺上叶后段炎性阴影,其中可见透亮区,血沉增快,结核菌素试验阳性,痰涂片结核菌阳性。其最理想的治疗方案是
2岁小儿,健康查体时在右肋缘下约1.5cm处触及肝脏,质软,表面光滑,边缘锐,无触痛,小儿一般情况好。其肝脏大属于
某城市要建一个科技软件园,下列有Ⅰ、Ⅱ、Ⅲ、Ⅳ四个位置(见题7图),()地块较适合。(每个地块约25hm2)
下列对法人转让房地产的纳税地点的说法正确的是( )。
《文物保护法》规定,文物工作贯彻的方针是()。
在对MMPI各因子分解释时,如果T分在30分以下或70分以上就属于()。
对照组实验设计属于
TheCanterburyTalesiswrittenintheformof
最新回复
(
0
)