【文章內(nèi)容簡介】 lecules better than red longer wavelength light. So the blue light gets bounced all over the sky and looks like it39。s ing from everywhere. Meanwhile, around sunset sunlight travels through so much atmosphere that just about all the blue is bounced away from the horizon, leaving all those reds and oranges behind. The sunset might look exclusively （獨(dú)有的）red and orange, but there39。s still some green and even blue light hidden in there, just far less than the other colors. But for us to notice the remaining green light, it needs to hit something that reflects green light much better than red. That39。s where water es in. Big tall threatening storm clouds are made of water droplets, and even though water is best at reflecting blue light, it can still reflect green pretty well, much better than reds and oranges, so under just the right conditions, the water in and around a cloud can bounce the green light hidden in the sunset right into our eyes making the sky look green. Still, none of the conditions that can turn skies green are unique to the clouds that produce tornadoes. Sometimes they just lead to lots of rain, and maybe some hail. So if you see huge storm clouds rolling in and a green tint （色調(diào)）in the sky, it doesn39。t necessarily mean there39。s about to be a tornado, but it does mean you should probably head indoors.（1）What can be the best title for the text? A.Why Do the Central United States Get TornadoesB.Do Green Skies Mean a Coming TornadoC.A Common Piece of Celestial FortunetellingD.Green Skies Are Unique to Clouds（2）Why are the skies blue in the daytime? A.Because only blue light can be bounced in the daytime.B.Because there is more blue light than light of other colors.C.Because blue light is bounced all over the sky.D.Because red light is weaker than blue light.（3）What does the underlined word it in paragraph 2 refer to? A.The sunset.B.Red light.C.Blue light.D.Water.（4）What can we learn about from the text? A.Storm clouds are made of water droplets and green light.B.Water can reflect red light as well as blue light.C.There are only red and orange lights in the sunsets.D.If you see a green sky, there will be a tornado.【答案】 （1）B（2）C（3）A（4）B 【解析】【分析】本文是一篇說明文，科學(xué)家發(fā)現(xiàn)天空呈現(xiàn)綠色并不是產(chǎn)生龍卷風(fēng)的云層所獨(dú)有的，有時(shí)它們會(huì)導(dǎo)致大量降雨，甚至冰雹，待在室內(nèi)或許是最好的選擇。 （1）考查主旨大意。通讀全文，根據(jù)第一段中的“there39。s a mon piece of celestial （天上的）fortunetelling that green skies mean a tornado is on its way.”和最后一段中的“Still, none of the conditions that can turn skies green are unique to the clouds that produce tornadoes. Sometimes they just lead to lots of rain, and maybe some hail.”可知，本文主要話題是關(guān)注綠色的天空是否意味著即將來臨的龍卷風(fēng)展開的，故選B。 （2）考查細(xì)節(jié)理解。根據(jù)第二段中的“Daytime skies are blue because blue shorter wavelengths of visible light tend to bounce off （反 射）air molecules better than red longer wavelength light.”可知，白天天空是藍(lán)色,因?yàn)樗{(lán)色短的波長的可見光會(huì)反射空氣分子比紅色的長波長光。故選C。 （3）考查代詞指代。根據(jù)第二段中的“The sunset might look exclusively （獨(dú)有的）red and orange, but there39。s still some green and even blue light hidden in there, just far less than the other colors.”可知，選A。 （4）考查推理判斷。根據(jù)第三段中的“But for us to notice the remaining green light, it needs to hit something that reflects green light much better than red. That39。s where water es in.”可知，水既能反射藍(lán)光，也能反射紅光，故選B。 【點(diǎn)評(píng)】本題考點(diǎn)涉及細(xì)節(jié)理解，代詞指代，推理判斷和主旨大意四個(gè)題型的考查，是一篇科普類閱讀，要求考生在捕捉細(xì)節(jié)信息的基礎(chǔ)上，進(jìn)一步根據(jù)上下文的邏輯關(guān)系，進(jìn)行分析，推理，概括和歸納，從而選出正確答案。5．犇犇閱讀理解 A good disguise keeps you hidden, right? Well, sometimes the best disguise is actually the most dazzling because research reveals that flashy metallic iridescence(金屬彩虹色) can visually puzzle predators, which allows colorful prey to survive another day. Those surprising results appear in the journal Scientific Reports. Shining iridescent color, which changes depending on the angle from which it39。s viewed, is favored by everything from birds to beetles and blossoms to butterflies. And in our research group we are of course interested in why this vivid metallic color is so widespread in nature. Karin Kjernsmo of the University of Bristol adds that in some cases the showy splashes of light are a sexual strategy. Here I would like to point out that in some species, particularly those that display strong sexual dimorphism(雌雄兩性), such as birds of paradise or some butterflies or fishes, the occurrence of iridescence is most likely driven by sexual selection. For example, in many of these cases it is the males that have these vivid iridescent colors and they use them in mate choice or they use them as a signal to attract mates. But iridescence also shows up in situations where reproduction is not an issue. So what we are studying now is whether natural selection imposed by predation(捕食行為) could explain the occurrence of iridescence in prey animals. The idea that eye173。catching colors could be used as a cover173。up isn39。t a new one. The father of camouflage theory, Abbott Thayer, really believed that iridescence should be categorized as a camouflage strategy. And he wrote in his famous lifework Concealing173。Coloration in the Animal Kingdom, already in 1909, that 39。brilliantly changeable or metallic colors are among the strongest factors in an animal39。s concealment39。. And this sounds like a pletely unreasonable thing to say, because how can colors that are both brilliant and changeable contribute to animal39。s concealment？ In a similar way, we were asking whether iridescence, due to its changeability, could work as a form of camouflage by preventing shape recognition. Kjernsmo and her colleagues trained bumblebees to associate a particular shape—a circle or an oval—with a sugar reward. And they found that the bees, when given a choice, would preferentially visit the shape they knew to be sweet. But when the shapes were iridescent, the bees had trouble telling them apart. It seemed that the strikingly iridescent surfaces on our targets visually broke up the otherwise recognizable shape of the targets, which made them hard to distinguish. As for making use of this method for hiding in plain sig