10.15 考研英语阅读题源外刊模拟试题【难度6.0】

Section II Reading Comprehension 

Part A 

Directions: Read the following four texts. Answer the questions below each text by choosing A, B, C or D. Mark your answers on the ANSWER SHEET. 

Text 2

Burglars have been running out of things they can safely leave behind. Footprints gave them away first, then fingerprints and stray fibres; even microscopic traces of DNA on tools and surfaces have been used to catch the careless. Now there is something new to worry about: genetic material floating in the air.

Everyone, innocent or guilty, sheds tiny fragments of skin, dandruff and saliva, and some of this hangs in the air as a cloud of personal debris that outlasts the person’s stay. In a new study, volunteers who staged mock burglaries could be identified from DNA drawn out of the air half an hour after they left. As with most forensic evidence, that alone would not prove wrongdoing, but it could raise difficult questions for anyone with no good reason to have been there.

The study borrows methods for capturing environmental DNA, the genetic traces that organisms leave in their surroundings. For more than two decades, ecologists have used such traces from water, soil and air to detect animals without having to see or catch them, from elusive pythons in a Florida wetland to the fish and eels of a Scottish loch.

Earlier work had shown that indoor air holds enough of this DNA to profile the people who use a room. To test its forensic potential, researchers recruited 22 households, half in Oslo and half in Adelaide. In each, a mock burglar who had never visited the house spent 15 minutes opening drawers and cupboards. Half an hour later, to mimic the delay before investigators arrive, a forensic team ran an air-sampling device in the kitchen for a couple of hours; they also swept surfaces, since airborne DNA settles as dust.

The results favoured burglars in Australia over those in Norway: intruders were matched in 82 per cent of cases in Oslo but only 36 per cent in Adelaide. The reasons are unclear, but may include environmental conditions, the number of people living in each house and how thoroughly rooms had been cleaned.

There are other complications. DNA in the air need not come from a recent visit: movement can stir up dust carrying old DNA, and DNA from people who never entered a house can be brought in on others’ clothes. The technique was also so sensitive that, despite elaborate precautions, some of the researchers’ own DNA ended up in the samples.

The lead researcher doubts that air samples will ever be reliable enough to offer decisive proof of guilt; she sees them as an investigative tool, one piece of a larger puzzle. It is too early for real cases: scientists must first understand why people shed different amounts of DNA, and laboratories must standardise their techniques. Even so, the team has spoken to police forces about one day helping them.

26. The author mentions pythons in a Florida wetland and fish in a Scottish loch to show that environmental DNA
A. has long helped ecologists detect animals they cannot see
B. was first developed to help solve crimes
C. is easier to collect from water than from air
D. can tell rare species apart from common ones

27. Why did the researchers wait half an hour before sampling the air?
A. To let airborne DNA settle into dust on the floor.
B. To imitate the time investigators would take to arrive.
C. To give the mock burglars time to leave the area.
D. To allow the sampling device to warm up fully.

28. What does the text say about the difference in success rates between Oslo and Adelaide?
A. It was caused mainly by how often the houses were cleaned.
B. It shows that Australian volunteers shed less DNA than Norwegian ones.
C. It resulted from the use of different methods of analysis.
D. Its causes are unclear, though several factors may play a part.

29. It can be inferred from Paragraph 6 that DNA found in the air of a house
A. belongs mostly to the researchers who collect it
B. disappears completely within half an hour of a visit
C. does not necessarily show that the person was there recently
D. can only be brought in by the people who live there

30. What is the lead researcher’s attitude towards using airborne DNA in real cases?
A. Confident that it will soon replace fingerprints.
B. Hopeful about its potential but aware of its limits.
C. Doubtful that the police will ever find it useful.
D. Unconcerned about the need to standardise methods.

附注：根据历年考研英语真题阅读题源外刊等，摘选最新文章，模拟仿真出题。

参考答案见以下。

Quick look: ABDCB

26.【正确答案】A
【解析】题型：例证/功能推理题
定位：第三段 “For more than two decades, ecologists have used such traces from water, soil and air to detect animals without having to see or catch them, from elusive pythons in a Florida wetland to the fish and eels of a Scottish loch.”
分析：两个例子都出现在"生态学家二十多年来用环境DNA探测动物"这一句中。作者借此说明环境DNA早已被生态学家用来探知难以看见的动物，法医研究是对这一成熟技术的借用。A项准确。
干扰项：[B]”最初是为破案而开发"与原文相反，原文明确是生态学家先使用，法医研究是"借用"其方法；[C]"从水中采集比从空气中更容易"无中生有，原文只说水、土壤、空气均可采样，没有比较难易；[D]"能区分稀有物种与常见物种"无中生有，两个例子只说明可以探测到动物的存在。

27.【正确答案】B
【解析】题型：细节理解题（设计缘由）
定位：第四段 “Half an hour later, to mimic the delay before investigators arrive, a forensic team ran an air-sampling device...”
分析：原文直接给出等待半小时的目的：模拟调查人员到达现场之前的延迟。B项对应。
干扰项：[A]”让空气中的DNA沉降为地面灰尘"张冠李戴，"空气中的DNA会沉降为灰尘"是研究者另外擦拭物体表面采样的理由，不是等待半小时的原因；[C]"给模拟窃贼时间离开该区域"无中生有，原文没有此说；[D]"让采样设备充分预热"无中生有，原文未提设备预热。

28.【正确答案】D
【解析】题型：细节理解题（程度辨析）
定位：第五段 “The reasons are unclear, but may include environmental conditions, the number of people living in each house and how thoroughly rooms had been cleaned.”
分析：奥斯陆的匹配率为82%，阿德莱德仅36%。对于差异成因，原文先说"原因不明"，再用 “may include” 列出几种可能因素。D项"成因不明，但可能有若干因素"与原文的不确定语气一致。
干扰项：[A]”主要由房屋清洁频率造成"程度夸大，清洁程度只是几种"可能因素"之一，原文并未确认其为主因；[B]"表明澳大利亚志愿者脱落的DNA更少"张冠李戴，"不同人脱落DNA量不同"出现在末段，是尚待弄清的问题，原文并未将其与两地差异挂钩；[C]"源于分析方法不同"无中生有，原文未提两地采用了不同的分析方法。

29.【正确答案】C
【解析】题型：推理判断题
定位：第六段 “DNA in the air need not come from a recent visit: movement can stir up dust carrying old DNA, and DNA from people who never entered a house can be brought in on others’ clothes.”
分析：原文指出空气中的DNA不一定来自最近的到访：走动会扬起带有旧DNA的灰尘，从未进屋的人的DNA也可能随他人衣物带入。因此在空气中检出某人的DNA，并不必然说明他刚到过现场。C项准确。
干扰项：[A]”大多属于采样的研究人员"程度夸大，原文只说研究人员自己的DNA"有一部分"混入样本；[B]"访问后半小时内完全消失"无中生有，研究恰恰在半小时后仍能检出DNA；[D]"只能由住户带入"与原文相反，原文明确从未进屋的人的DNA也可能经他人衣物带入。

30.【正确答案】B
【解析】题型：态度推理题
定位：末段 “The lead researcher doubts that air samples will ever be reliable enough to offer decisive proof of guilt... Even so, the team has spoken to police forces about one day helping them.”
分析：研究者的态度有两面。一方面，她认为空气样本不可能成为定罪的决定性证据，只是调查工具，距实际应用还早；另一方面，团队已与警方接触，期待将来协助办案。合起来是"看好其潜力，但清楚其局限"。B项准确。
干扰项：[A]”确信它很快会取代指纹"程度夸大，研究者明确说它不足以作为决定性证据，且距实际应用尚早；[C]"怀疑警方是否会觉得有用"与原文相反，团队已与警方接触，希望有朝一日协助办案；[D]"不关心方法标准化"与原文相反，原文明确指出实验室必须统一技术标准。

【参考译文】

对于窃贼而言，他们能“安全地”不留下任何痕迹的东西正变得越来越少。起初是脚印暴露了他们的行踪，随后是指纹和遗落的纤维；甚至工具或物体表面残留的微量DNA，也成了抓获粗心窃贼的证据。如今，他们又多了一项需要担心的事物：漂浮在空气中的遗传物质。

无论是否清白，每个人都会不断脱落微小的皮肤碎屑、皮屑和唾液微粒。这些物质会悬浮在空气中，形成一种“个人残留物云团”，即便在人离开后，它们依然会留存一段时间。在一项新研究中，志愿者们模拟了入室盗窃的过程；研究人员在他们离开半小时后，通过提取空气中的DNA，成功识别出了这些“窃贼”的身份。与大多数法医证据一样，仅凭这一点尚不足以证明其犯罪事实，但对于那些本无正当理由出现在现场的人来说，这可能会引发难以解释的质疑。

这项研究借鉴了“环境DNA”（即生物体在周围环境中留下的遗传痕迹）的采集方法。二十多年来，生态学家一直利用从水体、土壤和空气中提取的此类痕迹，在无需亲眼目睹或捕捉生物的情况下，对其进行探测——从佛罗里达湿地中行踪诡秘的蟒蛇，到苏格兰湖泊里的鱼类和鳗鱼，皆是如此。

此前的研究已表明，室内空气中蕴含的DNA足以勾勒出曾在此活动过的人员特征。为了验证其在法医鉴定方面的潜力，研究人员招募了22户家庭，其中一半位于奥斯陆，另一半位于阿德莱德。在每户家庭中，一名此前从未到访过的“模拟窃贼”会花15分钟翻动抽屉和橱柜。半小时后（旨在模拟调查人员抵达现场前的时间间隔），法医团队在厨房内运行了空气采样设备，持续数小时；他们同时还对物体表面进行了采样，因为空气中的DNA最终会沉降并形成灰尘。

结果显示，在奥斯陆的“模拟窃贼”比在阿德莱德的更容易被识别：奥斯陆案例中的身份匹配率为82%，而阿德莱德仅为36%。具体原因尚不明确，可能与环境条件、居住人数以及房间清洁程度等因素有关。

此外，还有其他复杂因素存在。空气中存在的DNA未必源自近期到访过该处的人：活动可能会扬起带有陈旧DNA的尘埃；而即便某人从未进入过室内，其DNA也可能通过他人的衣物被带入其中。此外，该检测技术极其灵敏，以至于尽管采取了周密的预防措施，研究人员自身的DNA还是混入了一些样本之中。

首席研究员对“空气样本能否提供定罪所需的决定性证据”持怀疑态度；她认为，空气样本更适合作为一种调查工具，是拼凑完整真相的一块拼图。目前将其应用于实际案件还为时过早：科学家们首先需要弄清为何不同个体释放出的DNA量存在差异，实验室也必须对相关检测技术进行标准化。尽管如此，该研究团队已与警方进行过沟通，探讨未来协助警方办案的可能性。

附注：