--解题技巧及典例剖析1.文章多用现在时态说明文通常是对客观事物或实例的介绍与说明，与时间的变化关系不大，所以文章常用现在时态。
2.语言简练、平实、准确，常采用客观描述说明文的目的主要是帮助读者认清事物，明白事理，所以语言简练、平实、易于理解，内容客观真实，很少含有带感情的词汇。
3.文章主题明确，层次分明说明文类完形填空往往在文章开头就点明说明对象，从而为学生们把握文章主题提供了有利1.利用说明文首句，明确说明对象典例1(2015·重庆高考B)Imagine the first days in a new time zone . Slow to respond to the 28______ , your body clock is confused. You're sleepy all day, but when it's time for bed, you can hardly fall asleep. Obviously you're 29 _________jet lag(时差反应）.28.A.flight B. change C. demand D. climate【解析】：下文的“jet lag(时差反应）”说明，在旅行时要适应时差。
29.A.suffering from B. working on C. looking into D. leading to 【解析】：上文的“hardly fall asleep”说明人们常常不能顺利地倒时差；suffer from“受折磨”。
【答案】：28.B29.A2.关注内在联系，把握说明顺序常见的说明顺序有时间顺序、空间顺序、逻辑顺序（如因果关系、果因关系、先主后次等）和认识顺序（如由此及彼、由浅入深、由局部到整体、由现象到本质、由具体到抽象等）。
典例2(2015·广东高考）How long can human beings live? Most scientists who study old age think that the human body is 1 _______to live no longer than 120 years. However,110 years is probably the longest that anyone could hope to live-if he or she is 2_______ healthy and lucky. Some scientists even say we can live as long as 130 years! Yet, our cells simply cannot continue to reproduce 3_______. They wear out, and as a result , we get old and 4 die .1.A.designed B. selected C. improved D. discovered【解析】：此处表示我们人体的设计就是最长活到120岁。
design“设计”。
pletely B. generally C. apparently D. extremely【解析】：根据上下文可知，此处表示110岁很可能是任何一个人可能会希望活的最长的时间了——如果一个人极其健康和幸运的话，extremely“极度，极其”。
3.A.rapidly B. harmlessly C. endlessly D. separately【解析】：这里表示人类细胞不能永无止境地自我繁殖，所以人才会变老。
endlessly“无止况地，无限地”。
4.A.eventually B. hopelessly C. automatically D. desperately 【解析】：get old的最终结果就是死亡，因此用eventually表示“最终”。
【答案】：1.A2.D3.C4.A3.逐句精读短文，逐题分析选项对特定的语境作深入的理解，克服“思维定式”，根据全文大意和文不离句、句不离文的原则逐项选择。
针对说明文独有的文体特点，解答时一定要注意从上下文意义、惯用法、固定搭配、逻辑推理、常识等角度去考虑和判断，并注意其内在联系。
完形填空---说明文专项练习第一节（共20小题；每小题1.5分，满分30分）阅读下面短文，从短文后各题所给的A、B、C和D四个选项中，选出可以填入空白处的最佳选项。
The small town of Rjukan in Norway is situated between several mountains and does not get direct sunlight from late September to mid-March—41 six months out of the year.Of course, we 42 it when the sun is shining," says Karin Ro, who works for the town’s tourism office. “We see the sky is43 , but down in the valley it’s darker—it’s like on a44 day.”But that 45 when a system of high-tech 46 was introduced to reflect sunlight from neighboring peaks（山峰）into the valley below. Wednesday, residents（居民）of Rjukan 47 their very first ray of winter sunshine: A row of reflective boards on a nearby mountainside were put to 48 . The mirrors are controlled by a computer that 49 them to turn along with the sun throughout the 50 and to close during windy weather. They reflect a concentrated beam（束）of light onto the town’s central 51 , creating an area of sunlight roughly 600 square meters. When the light 52 , Rjukan residents gathered together.“People have b een 53 there and standing there and taking 54 of each other," Ro says. "The town square was totally 55 . I think almost all the people in the town were there. "The 3,500 residents cannot all 56 the sunshine at the same time. 57 , the new light feels like more than enough for the town’s58 residents."It's not very 59 ,” she says, "but it is enough when we are 60 .”41.A. only B. obviously C. nearly D. precisely【答案】C【解析】考查副词。
从9月下旬到第二年的3月中旬，差不多（nearly)有半年的时间Rjukan 都得不到太阳光的直射。
A:仅，只有；B:明显地，显然；D:准确地。
42.A. fear B. believe C. hear D. notice【答案】D【解析】考查动词。
根据下文中的We see the sky可知此处表达我们注意到（notice)。
A:害怕；B:相信；C:听到，听说。
43.A. empty B. blue C. high D. wide【答案】B【解析】考查形容词。
当阳光照耀时天空是蔚蓝色的（blue)。
A:空的；C:高的；D:宽的。
44.A. cloudy B. normal C. different D. warm【答案】A【解析】考查形容词。
根据it's darker可知选A(cloudy)。
B:正常的；C:不同的；D:温暖的。
45.A. helped B. changed C. happened D. mattered【答案】B【解析】考查名词。
一套高科技设备被应用以来，这种情况就改变了(changed)。
A:帮助；C:发生；D:要紧。
46.A. computers B. telescopes C. mirrors D. cameras【答案】C【解析】考查名词。
从山峰往山谷底下反射太阳光，应该是采用了一套高科技的镜子（mirrors)。
A:电脑；B:望远镜；D:照相机，摄像机。
47.A. remembered B. forecasted C. received D. imagined【答案】C【解析】考查动词。
周三，Rjukan的居民接收到了（received)他们冬季里的第一束太阳光。
A:记起；B:预报，预测；D:想象，设想。
48.A. repair B. risk C. rest D. use【答案】D【解析】考查名词。
安装在附近山坡上的一排反光板被投入使用。
be put to use被投入使用。
A:维修，修理；B:风险；C:休息。
49.A. forbids B. directs C. predicts D. follows【答案】B【解析】考查动词。
这些镜子受电脑控制，电脑指示（directs)这些镜子随着太阳转动。
A:禁止；C:预言；D:跟随。
50.A. day B. night C. month D. year【答案】A【解析】考查名词。
太阳是在白天出来，所以这些镜子整个白天（day)都在电脑的指示下转动。
B:晚上；C:月；D:年。
51.A. library B. hall C. square D. street【答案】C【解析】考查名词。
这些镜子把一束集中的光线反射到镇中心的广场(square)上，形成一块面积大约为600平方米的日光区。