Scientists have been puzzled by the phenomenon that migrating birds fly not just in groups all the time,but in"V"formations and they have tried to figure out what benefit birds get from this particular formation.Now,a research group from University of London may have found the answer―migrating birds fly in a"V"to save energy,according to a study published in the journal Nature.
　　When a bird flaps(振翅)its wings,it stirs the air around it and causes it to move indifferent directions.Scientist found in the study that the air creates an upward-moving wave at the tips of the wings,which means that if a bird flies around the wingtips of another bird,it can get a boost(抬高)from the rising air and therefore use less energy to stay in the air.
　　Apart form the"free ride"strategy,scientists were also surprised to observe that migrating birds timed their wing beats and adjusted their positions in a very precise way to maximize the lifting effect while avoiding areas where the air move downward.
　　"They're able to sense what's going on from the bird in front,where this'good air'is coming from and now how to position themselves perfectly in it,"lead researcher Steven Portugal told BBC.
　　In fact,the"V"formation has long thought to help birds fly more efficiently(效率搞地).A previous study showed that birds'heart rates went down when they were flying together in a"V"formation.Jet fighters were also found to be able reduce their energy use by up to 18%by staying near the wingtips of other jet fighters.Both of these findings led scientists to suspect that the"V"formation had an efficiency purpose,but until now they still lack proof.
　　"For scientists,the new study provides an insight into an interesting natural phenomenon.But it could mean even more for aircraft companies—helping them understand how they can imitatethat with their plane formations to save fuel,said Portugal."
　　1、According to the recent study,when birds migrate.
　　A.they don't change their lead birds during the whole journey
　　B.they fly in"V"formations to protect themselves against enemies
　　C.they form the shape of a"V"to make best use of the lifting effect
　　D.the air they stir around makes it hard for the birds behind to fly fast
　　参考答案：C
　　参考解析：推理题。根据文章第三段Apart form the"free ride"strategy,scientists were also surprised to observe that migrating birds timed their wing beats and adjusted their positions in a very precise way to maximize the lifting effect while avoiding areas where the air move downward.可知候鸟按照V字形飞行是为了更好地利用鸟儿拍打翅膀带来的lifting的影响，让飞行的效率更高。故C正确。
　　2、What is the author's purpose in writing this article?
　　A.To explain how birds benefit from migration.
　　B.To introduce how migrating birds find their way.
　　C.To tell some applications of migrating birds'"V"formations.
　　D.To report new findings about migrating birds'"V"formations.
　　参考答案：D
　　参考解析：推理题。根据文章主题段第一段最后一句Now,a research group from University of London may have found the answer―migrating birds fly in a"V"to save energy,according to a study published in the journal Nature.可知本文是对候鸟使用V字形飞行的原因的研究的新的发现。故D正确。
　　3、The underlined word"imitate"in the last paragraph most probably means"".
　　A.use
　　B.copy
　　C.change
　　D.learn
　　参考答案：B
　　参考解析：猜测词义题。根据本句But it could mean even more for aircraft companies—helping them understand how they can imitate that with their plane formations to save fuel,said Portugal."可知这一新发现能够帮助那些飞机制造商，更好地理解他们如何模仿鸟儿的这一飞行特点来改造飞机以节省燃料。该该词是指“模仿”，故B正确。
　　4、What is the significance of the new study according to this article?
　　A.It might inspire aircraft companies to think of ways to improve efficiency.
　　B.It has proved that the"V"formation can improve in efficiency in many fields,
　　C.It has led scientists to discover that birds'heart rates go down when they fly in a"V".
　　D.It shows that the best formation of jet fighters in battle should be a"V"formation.
　　参考答案：A
　　参考解析：推理题。根据文章最后2行.But it could mean even more for aircraft companies—helping them understand how they can imitate that with their plane formations to save fuel,said Portugal."可知飞机制造商可以利用这一研究结果来提高飞机飞行的效率。故A正确。
　　参考译文：
　　科学家们一直困惑于这样一种现象：迁徙的鸟类不只是成群结队地飞行，而是以“V”字形飞行，他们试图弄清楚鸟类从这种特殊的形态中得到什么好处。现在，伦敦大学的一个研究小组可能已经找到了答案——根据发表在《自然》杂志上的一项研究，迁徙的鸟类飞在“V”型飞行器上以节约能源。
　　当一只鸟拍打它的翅膀时，它会搅动周围的空气，使它向不同的方向移动。科学家在这项研究中发现，空气在翼尖处产生向上运动的波，这意味着如果一只鸟在另一只鸟的翼尖周围飞行，它可以从上升的空气中获得提升（_），因此在空气中停留所需的能量更少。
　　除了“自由飞行”策略外，科学家们还惊讶地发现，迁徙的鸟类会调整翅膀拍打的时间，并以非常精确的方式调整它们的位置，以最大限度地提高升力，同时避开空气向下移动的区域。
　　首席研究员史蒂文·葡萄牙告诉英国广播公司：“他们能够感觉到前方的鸟在做什么，这里的‘好空气’来自哪里，现在如何将自己完美地安置在那里。”
　　事实上，“V”形构造一直被认为可以帮助鸟类更有效地飞行。先前的一项研究表明，当鸟类以“V”字形飞行时，它们的心率会下降。喷气式战斗机也被发现能够通过靠近其他喷气式战斗机的翼尖减少高达18%的能源消耗。这两个发现都让科学家们怀疑“V”形形成有一个有效的目的，但直到现在他们仍然缺乏证据。
　　对于科学家来说，这项新的研究提供了一种对有趣的自然现象的洞察。但葡萄牙表示，这对航空公司来说可能意味着更多——帮助他们了解如何通过飞机编队来模仿这一点，以节省燃料。”