【正文】 根據(jù)最后一段中的“Street trees also benefit from higher levels of nitrogen (氮）in rainwater. Nitrogen helps plants grow. Waste gases from gasburning cars also contain nitrogen, thus enriching city air with nitrogen. Later, rainwater may wash much of it to the ground.”可知，與生長在森林中的樹木相比，城市里的樹木長得更快是因為它們無需與鄰近的樹木爭奪光照，也能得到更多的氮量，還更容易得到水。故選A。 （2）考查細(xì)節(jié)理解?？梢酝茢?，二氧化碳可以防止地球變得不適合居住。 （1）考查推理判斷。Why fastergrowing trees absorb more C02.【答案】 （1）D（2）A（3）A（4）B 【解析】【分析】本文是一篇說明文。Why city living makes trees die young.C.How urban trees can live longer.They can enjoy more shade from neighbors.D.They are more likely to access growth promoters.B.D.To check whether they were healthy.B.To know about their growth rates.It results from the widespread burning of fossil fuels.D.It is one of the side effects of greenhouses.B. tracking, the researchers found city trees absorbed four times as much carbon from the air as forest trees. However, they were twice as likely to die. So over the lifetime of each type of tree, forest trees actually absorbed more CO2.s diameter increases as it grows, just as a person39。 t been much data on whether city trees grow, die and absorb CO2 at the same rate as forest trees do. So some researchers decided to find out. As we all know, the earth would be freezing or burning hot without CO2. However, CO2 is a greenhouse gas, meaning it traps energy from the sun as/heat. That makes temperatures near the ground rise. Human activities, especially the widespread burningof fossil(化石)fuels, have been sending extra greenhouse gases into the air. This has led to a rise in average temperatures across the globe. 7．閱讀理解 故選D。 mouths water?”根據(jù)Smithsonian雜志，世界上大約20%的人容易招蚊子咬。 （4）考查主旨大意?？芍恼陆ㄗh我們可以通過穿淺色衣服來避免蚊子叮咬。 （3）考查細(xì)節(jié)理解。t pregnant.”對二氧化碳的喜歡使得孕婦很容易被蚊子咬，因為她們比正常相同年齡，相同體型的人呼出多余21%的二氧化碳，可知，孕婦呼出更多的二氧化碳，所以更招蚊子咬。 （2）考查細(xì)節(jié)理解。它們通過聞人和動物呼出的二氧化碳來鎖定目標(biāo)；以及第五段中的“Mosquitoes start orienting themselves to carbon dioxide and keep flying upwind as they sense higher concentrations”蚊子開始飛向有二氧化碳的地方，當(dāng)它們感知到高濃度的二氧化碳時，就保持逆流飛行，可知，蚊子通過感知二氧化碳的增加來鎖定目標(biāo)。 （1）考查細(xì)節(jié)理解。t worry. Some simple tips can help ward them off. Scientists remend that we use insect repellent (驅(qū)蟲劑) and wear lightcolored clothing.（1）How do mosquitoes locate their targets, according to the article? seeking out bright clothes. identifying different blood types. sensing an increase of carbon dioxide. following bigger crowds.（2）Why are pregnant women more likely to be bitten by mosquitoes? larger size helps mosquitoes to see them. breathe out more CO2. are more likely to sweat. body temperatures are higher.（3）How does the article advise you to avoid mosquitoes? regularly. lightcolored clothing. your skin dry and clean. indoors in the evening.（4）What39。 According to Live Science, mosquitoes can lock onto targets from up to 50 meters away. At this distance, what we wear has a huge effect. Due to their vision (視覺), people wearing dark colors are more likely to bee targets. t pregnant. t get bitten as much ... as adults, US professor Ted Rosen told Science Alert. Joop van Loon, an entomologist at Wageningen University in the Netherlands, told Live Science, Mosquitoes start orienting (使......朝向) themselves to carbon dioxide and keep flying upwind as they sense higher concentrations (濃度).Mosquitoes are especially active in the late afternoon. While flying along, they use their sense of smell to find possible targets. They find victims (攻擊對象) by smelling the carbon dioxide (CO2) breathed out by humans and animals. That39。t tell what your blood type is from a faraway place. Jonathon Day, a professor of medical entomology (昆蟲學(xué)) at the University of Florida in the US, told NBC it39。 mouths water?If this is you, you39。Some people sit outside for hours without getting bitten by mosquitoes, but it always seems like you39。 【點評】本題考點涉及細(xì)節(jié)理解，推理判斷和主旨大意三個題型的考查，是一篇環(huán)保類閱讀，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。故短文的最佳標(biāo)題為海洋快喘不過氣來了符合題意。通讀全文可知，短文說明了海洋氧含量下降是一個與氣候變化有關(guān)的令人擔(dān)憂的趨勢，海洋氧含量下降的原因以及對海洋生物的影響和對其生存的威脅。故選A。所以海洋中氧含量減少迫使動物離開自己的棲息地，去氧氣含量較高的地區(qū)尋求庇護(hù)。根據(jù)倒數(shù)第二段中的Ocean animals large and small, however, respond to even slight changes in oxygen by seeking refuge in higher oxygen zones or by adjusting behavior, Oschlies and others in his field have found. These adjustments can expose animals to new predators or force them into foodscarce regions. 可知，然而，Oschlies和他所在領(lǐng)域的其他人發(fā)現(xiàn)，無論大小，海洋動物對氧氣的微小變化都有反應(yīng)，它們在較高的含氧區(qū)尋求庇護(hù)，或是調(diào)整行為。故選C。因為所有的氧氣都進(jìn)入了表面，所以較少的與海洋水的混合意味著更深的海洋含氧量更少。根據(jù)第三段中的 as polar sea ice melts, it forms a layer of water above colder, more salty sea waters. This process creates a sort of lid that can keep currents from mixing surface water down to deeper depths. And because all oxygen enters the surface, less mixing means less of it at depth.可知，當(dāng)極地海冰融化時，它會在更冷、更咸的海水上形成一層水。故選A。其他地區(qū)的降幅較小，全球平均降幅為2%。根據(jù)第二段中的It is no surprise to scientists that warming oceans are losing oxygen, but the scale of the drop calls for urgent attention. Oxygen levels in some tropical (熱帶的) regions have dropped by an astonishing 40 percent in the last 50 years, some recent studies reveal. Levels have dropped less significantly elsewhere, with an average loss of 2 percent globally.可知，對于科學(xué)家來說，變暖的海洋正在失去氧氣并不奇怪，但這種下降的規(guī)模需要緊急關(guān)注。同時介紹了海洋氧含量下降的原因以及對海洋生物的影響和對其生存的威脅。D.The Survivability of Ocean AnimalsB.Some animals reduce their movements in order to absorb more oxygen.（4）Which of the following is the best title of the passage? A.Ocean acidification is more serious a problem than deoxygenation.C.Ocean deoxygenation changes some animals39。The surface polar ice water prevents oxygen going down.D.Polar ice melting consumes much oxygen in the ocean.B.The alarmingly changeable oxygen levels in the ocean.D.The worsening deoxygenation in the warming ocean.B. Ocean animals large an