科普说明文是高考英语阅读理解的一种常见体裁，着重考查考生对于语篇的理解能力以及信息处理能力，近几年全国卷和各地自主命题卷均涉及到这类文章。因此，准确把握此类文章的选材、命题特点、掌握相应的阅读策略与解题技巧对于考生备战高考非常重要。
高考英语阅读理解科普类文章思想性和时代感强，题材涉及发明创造、科技创新、科技与生活、科学研究等。文章体裁一般为说明文，语篇主要来源于英美主流报刊、杂志和网站，文章的遣词造句地道，思维逻辑独具英语语言的特点。这些文章和题目不仅能让考生体会到科学的无限趣味和实际功用，而且促使考生深入思考科技创新在人类生活和发展过程中起到的重要作用。
科普类文章的理论性和逻辑性强、篇幅长、生词多、句式结构复杂。文本结构一般包括五个部分：标题（headline）、导语（introduction）、背景（background）、主干（main body）和结尾（ending）。标题高度精辟地概括文章中心思想。高考中科普类阅读理解一般不给标题，反而经常要求考生选择最佳标题。导语一般位于整篇文章的首段。背景则交代研究的起因或者问题现状。主干部分介绍研究所取得的突破，作者往往会详细介绍研究的理论构架、研究对象、研究方法、具体的实验、统计等过程。结尾通常会再次对中心进行概括、重述研究成果、后续研究的方向等，与导语相呼应。
从近年全国卷和各地高考试卷中科普类阅读命题的统计来看，高考阅读理解六种命题类型都有所体现。命题尊重语篇的文体特征和行文特点，考查了考生理解说明文语篇的能力，以及灵活运用各种阅读策略提取、归纳所读信息的能力，尤其加大了对概括能力和推断能力等高阶思维能力的考查。
任何一种阅读方法或技巧的使用，都是由语篇特点和试题本身的要求决定的，考生应根据不同的体裁和试题要求采取不同的策略。下面向同学们介绍在解科普类阅读理解题目时常用的阅读策略和解题技巧。1. 运用语篇结构（text structure），概括全文主旨大意，明晰写作意图。科普说明文主题鲜明、脉络清晰，行文结构模式较为固定。弄清文本结构有助于把握文章主旨和阅读重点。高考科普类说明文一般分为两种类型：实验研究型和介绍说明型。除了遵循上述文本结构的几个部分的模式外，作者在谋篇布局上常使用以下说明方法：描述法（description）（包括举例子、下定义、列数据等）、因果法（cause and effect）、问题与对策法（problem and solution）。
实验研究型文章一般会以实验的过程进展为线索，多用描述法、问题与对策法等方法，通过列数据、做对比等来说明新的科学研究发现及其产生的影响。介绍说明型文章通常是介绍一种新产品、新技术，更多运用描述法从功能、用途、材料和市场前景等方面进行介绍。
同学们在阅读时，首先用略读法快速浏览每段的首尾句，分析原文的文本结构，然后根据作者谋篇布局的逻辑线索归纳主旨大意。如果文章中含有标题、副标题、图片等，在概括全文主旨大意和写作目的时需要重点考虑。根据英语说明文思维模式特征，作者一般都会开门见山，直奔主题。结尾通常也是中心思想的概括，并与导语相呼应。因此在做主旨大意、写作意图和最佳标题等题目时，需要重点关注首尾段落里面高频复现的词汇和内容。导语、主体和结尾是有机整体，解题时要综合起来进行判断。2. 利用文中语境线索（context clues），分析长难句，进行逻辑推理判断。
英语文章中有大量的词汇是作者用来联系句子与句子，从而使整篇文章前后贯通、语义明确的。标志词（signal words）就是表明句子间和段落间的逻辑关系、具有词义、语法结构标志作用的词或词组。句子间的逻辑关系和衔接手段不外乎列举、原因、结果、让步、对照、补充、目的、条件等。如表示列举的连词：for example, for instance; 表罗列的连词：first, second, third; to begin with, to conclude；表转折的连词：however, but, whereas; 表示原因的连词：because, since, as；表示结果的连词：so, therefore, thus, consequently, as a result；表示对照的连词：on the contrary, by contrast, in comparison；表示目的的连词：so that, in order that等。标志词就像指路牌一样，指明作者思路发展的方向和思路之间的逻辑联系。还有一些出现在术语、抽象概念、长难句前后的同义词、近义词等，都是用以理解文章的语境线索。标志词前后的信息往往都是命题和答题的主要线索或依据，因此，标志词的识别对考生更快更好地理解文章具有举足轻重的作用。
同学们在阅读解题时，第一步可以浏览全文，掌握中心大意。第二步可以根据题干要求，用查读法（scanning）再快速定位到相关段落。第三步可以重点搜索段内的标志词，利用标志词所提供的逻辑关系找到细节信息，如数据、例子、原因和结果等。如果句子成分复杂，有生词，也不要烦躁退缩，分析主句和从句或非谓语动词之间的关系，抓住行文逻辑的标志词，层层剖析，露出主干部分，就能明晰句意，弄懂作者的真实意图。3. 谙熟选项设置规律，对比原文，去伪存真。
高考作为一种成熟的考试体系，在选项设置上有章可循。掌握一定的规律对甄别正确选项大有帮助。一般说来，正确选项为文中内容的“同义替换”或者“归纳概括”。而干扰项分为“张冠李戴”、“偷梁换柱”、“无中生有”和“以偏概全”四种类型。
“张冠李戴”是命题者把文章作者的观点与他人的观点混淆起来，或者把文中不同地方的信息拼接在一起从而改变了原文的意思。
“偷梁换柱”类型是用了与原文相似的句型结构和大部分相似的词汇，却在不易引人注意的地方换了几个表示程度、限定的词汇，造成句意的改变。
“无中生有”类型往往是生活的基本常识和普遍接受的观点，貌似非常正确，但在原文中并无相关的信息支持，这种选项的设置往往与问题的设问毫不相干。
“以偏概全”则是以局部代替整体，进行不合理关联或者不准确的概括。在下文的例子中，同学们可以更加清楚直观地了解干扰项的特点，在解题时，绕开陷阱，去伪存真。Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills (垃圾填埋场), and up to 12 million tons pollute the oceans. So far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.
Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms’ chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste (糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass – apparently broken down by enzymes (酶) from the worms’ stomachs. Their findings were published in Current Biology in 2017.Federica Bertocchini, co-author of the study, says the worms’ ability to break down their everyday food – beeswax – also allows them to break down plastic. “Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well,” she explains. “The wax worm evolved a method or system to break this bond.”Jennifer DeBruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes (肠道微生物)?
Bertocchini agrees and hopes her team’s findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process – not simply “millions of worms thrown on top of the plastic.”阅读思路点拨：
全文围绕一种可以降解塑料的大蜡螟虫子的展开，有可能解决社会生活中塑料污染问题。文章具有科普类说明文体的典型特征，属于实验研究型。文章有标题和配图，考生在阅读时要把标题的关键词worm和plastic牢记于心。第一段导语点题。第二至四段为主干分别描述了研究过程、虫子能降解塑料的原理、后续研究的方向。结尾就如何运用这种方法进行展望。题目设置既注重对语篇整体理解的考查，也关注事实性信息的考查。43. What can we learn about the worms in the study?
A. They take plastics as their everyday food.
B. They are newly evolved creatures.
C. They can consume plastics.
D. They wind up in landfills.
解题技巧点拨：
细节理解题，答案选C。根据文章第二段中的“The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it.”可知这些虫子可以消耗聚乙烯购物袋，即塑料袋。A选项具有干扰性，根据原文第三段中第一句提到“这种虫子以蜂蜡为日常食物，他们消化蜂蜡的能力使其能够降解塑料。”可判断A项不对，属“偷梁换柱”干扰类型。D选项属于“张冠李戴”干扰类型。44. According to Jennifer DeBruyn, the next step of the study is to _____.
A. identify other means of the breakdown
B. find out the source of the enzyme
C. confirm the research findings
D. increase the breakdown speed解题技巧点拨：细节理解题，答案选B。根据题干信息和文中标志词the next step定位原文第四段最后两句话，可推知下一步研究是要找到酶的来源。45. It can be inferred from the last paragraph that the chemical might __.
A. help to raise worms
B. help make plastic bags
C. be used to clean the oceans
D. be produced in factories in future解题技巧点拨：推理判断题，答案选D。根据文章最后一段 “But she expects using the chemical in some kind of industrial process – not simply ‘millions of worms thrown on top of the plastic.’”可知研究者希望那些化学物品可以工业化生产，而不是将许多虫子直接扔在塑料上。46. What is the main purpose of the passage?
A. To explain a study method on worms.
B. To introduce the diet of a special worm.
C. To present a way to break down plastics.
D. To propose new means to keep eco-balance.
解题技巧点拨：主旨大意题，根据全文中心思想找出作者的写作意图，答案为C。通过标题和首尾段，可知全篇文章的核心是阐述虫子和降解塑料之间的关系，C选项中a way指的就是文中的worm, 它和plastics是全文的研究对象，而break down 指出了两者的关联，所以C项概括了全文的写作意图。A选项“以偏概全”，没有包含worms和plastics之间的关系。B和D选项偏离文章中心。There’s a new frontier in 3D printing that’s beginning to come into focus: food. Recent development has made possible machines that print, cook, and serve foods on a mass scale. And the industry isn’t stopping there.
Food productionWith a 3D printer, a cook can print complicated chocolate sculptures and beautiful pieces for decoration on a wedding cake. Not everybody can do that – it takes years of experience, but a printer makes it easy. A restaurant in Spain uses a Foodini to “recreate forms and pieces” of food that are “exactly the same,” freeing cooks to complete other tasks. In another restaurant, all of the dishes and desserts it serves are 3D-printed, rather than farm to table.
Sustainability (可持续性)The global population is expected to grow to 9.6 billion by 2050, and some analysts estimate that food production will need to be raised by 50 percent to maintain current levels. Sustainability is becoming a necessity. 3D food printing could probably contribute to the solution. Some experts believe printers could use hydrocolloids (水解胶体) from plentiful renewables like algae (藻类) and grass to replace the familiar ingredients (烹饪原料). 3D printing can reduce fuel use and emissions. Grocery stores of the future might stock “food” that lasts years on end, freeing up shelf space and reducing transportation and storage requirements.
NutritionFuture 3D food printers could make processed food healthier. Hod Lipson, a professor at Columbia University, said, “Food printing could allow consumers to print food with customized nutritional content, like vitamins. So instead of eating a piece of yesterday’s bread from the supermarket, you’d eat something baked just for you on demand.”
ChallengesDespite recent advancements in 3D food printing, the industry has many challenges to overcome. Currently, most ingredients must be changed to a paste (糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways. On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad. Some experts are skeptical about 3D food printers, believing they are better suited for fast food restaurants than homes and high-end restaurants. 阅读思路点拨：文章的文本结构属于“介绍说明型”，逻辑性强、条理清楚。采用总分结构，用描述法分别从食品生产、可持续性、营养价值和面临的挑战四个方面介绍了3D打印技术在食品生产方面所取得的进展。在概括文章主旨大意时，要重点关注第一段和四个副标题。
46. What benefit does 3D printing bring to food production?
A. It helps cooks to create new dishes.
B. It saves time and effort in cooking.
C. It improves the cooking conditions.
D. It contributes to restaurant decorations.解题技巧点拨：推理判断题，答案选B。根据文章Food production中叙述了没有经验的人可以用3D打印机做出婚礼蛋糕上复杂的巧克力雕塑和其它美丽的装饰，餐厅能够用3D打印机打印出相同形状的食物，以便让厨师有时间做其他工作，从而可以推断出3D打印的优势是节省了做饭的时间和精力。本段内的but和another都是标志词，可知作者举了两个例子，用以说明3D打印方式的方便和快捷。47. What can we learn about 3D food printing from Paragraph 3?
A. It solves food shortages easily.
B. It quickens the transportation of food.
C. It needs no space for the storage of food.
D. It uses renewable materials as sources of food.解题技巧点拨：细节理解题，答案选D。根据文章第三段“Some experts believe printers could use hydrocolloids (水解胶体) from plentiful renewables like algae (藻类) and grass to replace the familiar ingredients (烹饪原料).”可知，3D打印机可以使用可再生材料作为食物来源。根据第三段最后一句话可知“3D食品打印技术降低了运输和储存的成本”，由此判断A、B、C项错误。48. According to Paragraph 4, 3D-printed food ________.
A. is more available to consumers
B. can meet individual nutritional needs
C. is more tasty than food in supermarkets
D. can keep all the nutrition in raw materials解题技巧点拨：推理判断题，答案选B。根据文章第四段“Food printing could allow consumers to print food with customized nutritional content, like vitamins.”可以推断出3D打印出来的食物可以满足个人营养需求。文中的customized一词，考生可以利用构词法猜测出“与消费者本人有关的”的意思，再结合全句可以判断出“个性化的”、“定制的”的意思。49. What is the main factor that prevents 3D food printing from spreading widely?
A. The printing process is complicated.
B. 3D food printers are too expensive.
C. Food materials have to be dry.
D. Some experts doubt 3D food printing.解题技巧点拨：细节理解题，答案选C。根据文章最后一段“On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad.”可知，阻止3D打印食物进一步广泛使用的重要原因是原料必须是干的，含水多的肉和牛奶不能应用于3D打印因为很容易坏。该句标志词“because”后面的内容为选择提供了依据。50. What could be the best title of the passage?
A. 3D Food Printing: Delicious New Technology
B. A New Way to Improve 3D Food Printing
C. The Challenges for 3D Food Production
D. 3D Food Printing: From Farm to Table解题技巧点拨：主旨大意题，答案选A。文章主要介绍了3D打印技术在食物上的应用取得了进展，但目前仍面临着许多方面的挑战。最佳标题有三种特征：概括性、针对性、醒目性。概括性是标题用词在最大程度上体现文章主题。针对性指用词直指说明对象。醒目性是为了吸引读者，唤起阅读兴趣。A项的标题满足这三个特性，为最佳标题。B项文中没有涉及，C项虽然有所涉及，但是作为全文标题就以偏概全了。D选项偏题，背离文章主题。同学们要想做好科普类说明文的阅读理解题，首先要掌握这些文章的结构特点和语言特征，运用有效的阅读策略，真正地读懂并理解它。第二，在复习备考时要回归课本中的科普类说明文，研究课文所涉及的话题、篇章结构、长难句语法结构。第三，加强原版科普类文章阅读，如英美国家主流科普类杂志，了解影响我们生活的世界科技创新和突破。长期坚持，既能够积累常见的科普词汇，形成新思维，还能够提高解答这类题型的能力。
