for roughly a fifth of all human-caused greenhouse gas emissions. Fertilizer runoff also leads to other problems, like the algae blooms in Lake Eerie and the Dead Zone in the Gulf of Mexico.
However, following dietary guidelines would reduce those impacts, especially in wealthy countries like the US. “Most of the reductions come from meat and dairy，” which have an outsized impact on land use and pollution, and are a major source of greenhouse gases.(That's partly due to cow farts. Seriously.) Following the suggestions would also mean eating fewer calories, since many people here eat more than they need.
Overall, in high-income countries, Behren's team estimates that following the rules could result in as much as a 17 percent reduction in land use, a 21 percent reduction in nutrient pollution, and a 25 percent drop in agricultural greenhouse gas emissions. Cutting down on how much food we waste—which is roughly a third in the US—could help even more. The results are in the Proceedings of the National Academy of Sciences.
Of course, people are notoriously bad at following diets. But: “These nationally recommended guidelines do actually have a knock-on effect on other areas of policy making. So if I'm developing a new healthy-eating-for-schools program then that's going to be based off a lot of detail that I get from the nationally recommended guidelines. So while it might not necessarily be the case that people follow directly … they actually are quite influential on the preparation of other advice.”
It seems that a smaller environmental footprint and a healthier lifestyle could go hand in hand.
58. Which of the following statement will Paul Behrens approve of?
A. Following a nationally recommended diet can have similar impacts in different countries. B. Following a nationally recommended diet can do good to our health. C. Not all the countries have recommended diets in an explicit manner.
D. Some high-income nations don't mention the diet explicitly for its impacts can be ignored.
59. What do the underlined words “takes a big toll on” in paragraph 3 probably mean? A. shows signs of
C. takes full advantage of
B. has a bad effect on D. makes up for
60. Which of the following is TRUE according to the passage?
A. Food production can lead to about 20 percent of human-caused greenhouse gas with only a third of the ice-free land used.
B. It is estimated that following dietary guidelines can lead to decrease in more land use than in nutrient pollution.
C. Paul Behrens' new program concerning healthy eating for schools is likely to be based on national nutrition guidelines.
D. Some wealthy countries tend to reduce meat and dairy though the other areas of policy making isn't effected much. 【答案】58. C 59. B 60. A 【解析】
这是一篇说明文。文章主要讲了营养指南对地球也有利。通过膳食指南，似乎可以减轻对环境的伤害，人类自己也可以过上健康的生活，二者可以兼得。 【58题详解】
推理判断题。答案定位在第二段“What we found is that impacts vary across nations, but in the high-impact nations, in general, you can see that, if you follow a nationally recommended diet, despite the fact that these diets don't mention explicitly—or most of them don't explicitly mention—environmental impacts, that you are going to have lower environmental impacts due to that.（“我们发现（营养膳食指南的）影响因国家而异，但总的来说，在影响力较大的国家，如果你遵循国家推荐的膳食指南，即使这些膳食并未明晰对环境的影响，或者大多数膳食没有明确说明这一点，但是你对环境的影响会因为遵循指南而减轻。）由此推断出“并非所有国家都以明确的方式推荐饮食”，这个观点Paul Behrens会赞成，故选C。 【59题详解】
词义猜测题。下文A third of the ice-free land on Earth is used for agriculture, and according to some estimates, producing food accounts for roughly a fifth of all human-caused greenhouse gas emissions. Fertilizer runoff also leads to other problems, like the algae blooms in Lake Eerie and the Dead Zone in the Gulf of Mexico.说地球上三分之一的无冰区被用于农业生产，根据一些估算，食物生产大约占到了人类造成的温室气体排放量的五分之一。肥料径流也导致了其他问题，例如伊利湖的藻类爆发以及墨西哥湾的死亡区域。由此推断出划线词所在的句子意思是我们所吃的食物给环境带来了巨大代价。takes a big toll on意思是付出了巨大的代价，A. shows signs of显示…迹象；B. has a bad effect on付出了巨大的代价；C. takes full advantage of充分利用；D. makes up for弥补，故选B。
【60题详解】
细节理解题。答案定位在第三段A third of the ice-free land on Earth is used for agriculture, and according to some estimates, producing food accounts for roughly a fifth of all human-caused greenhouse gas emissions.（地球上三分之一的无冰区被用于农业生产，根据一些估算，食物生产大约占到了人类造成的温室气体排放量的五分之一。）由此可知。A选项的描述“粮食生产可导致约20%的人为造成的温室气体，而只使用了三分之一的无冰土地”正确，故选A。
C
A good disguise keeps you hidden, right? Well, sometimes the best disguise is actually the most dazzling because research reveals that flashy metallic iridescence(金属彩虹色) 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 it'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(雌雄两性), 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(捕食行为) could explain the occurrence of iridescence in prey animals.”
The idea that eye-catching colors could be used as a cover-up isn'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
Concealing-Coloration in the Animal Kingdom, already in 1909, that ‘brilliantly
changeable or metallic colors are among the strongest factors in an animal's concealment’. And this sounds like a completely unreasonable thing to say, because how can colors that
are both brilliant and changeable contribute to animal'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 sight, “Any practical applications is of course directly linked to any industry that has an interest in camouflage, that is how to conceal objects or make them more difficult to recognize.” The researchers are currently conducting experiments with birds, which often prey on iridescent insects to see if it helps to have a bird's-eye view.
61. According to the passage, iridescence is not made use of by animals to ________. A. live a little longer by escaping their predator(捕食者) B. catch the attention of their mates C. conceal themselves when in danger D. catch sight of more colorful preys
62. From the study in the last paragraph, we can learn that ________. A. Bees can always tell the difference between a circle and an oval
B. Bees are creatures that are fascinated by sweet things that are iridescent
C. If a circle, with a sugar reward, is iridescent, the bees may have difficulty finding it
D. Bees are likely to prefer circles to ovals, whether they are iridescent or not 63. What will be talked about in the following paragraph? A. Whether there are any differences between bees and birds. B. Some industries that have great interest in camouflage. C. Why birds are not effected by iridescent insects. D. Which camouflage theory applies more to birds.
64. Which of the following might serve as the best title of the passage? A. A famous camouflage strategy
B. Metallic iridescent as the best