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

參考答案：C

參考解析：推理題。根據文章第三段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.可知候鳥按照V字形飛行是為了更好地利用鳥兒拍打翅膀帶來的lifting的影響，讓飛行的效率更高。故C正確。

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.

參考答案：D

參考解析：推理題。根據文章主題段第一段最后一句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.可知本文是對候鳥使用V字形飛行的原因的研究的新的發現。故D正確。

3、The underlined word"imitate"in the last paragraph most probably means"".

A.use

B.copy

C.change

D.learn

參考答案：B

參考解析：猜測詞義題。根據本句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."可知這一新發現能夠幫助那些飛機制造商，更好地理解他們如何模仿鳥兒的這一飛行特點來改造飛機以節省燃料。該該詞是指“模仿”，故B正確。

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.

參考答案：A

參考解析：推理題。根據文章最后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."可知飛機制造商可以利用這一研究結果來提高飛機飛行的效率。故A正確。

參考譯文：

科學家們一直困惑于這樣一種現象：遷徙的鳥類不只是成群結隊地飛行，而是以“V”字形飛行，他們試圖弄清楚鳥類從這種特殊的形態中得到什么好處?，F在，倫敦大學的一個研究小組可能已經找到了答案——根據發表在《自然》雜志上的一項研究，遷徙的鳥類飛在“V”型飛行器上以節約能源。

當一只鳥拍打它的翅膀時，它會攪動周圍的空氣，使它向不同的方向移動?？茖W家在這項研究中發現，空氣在翼尖處產生向上運動的波，這意味著如果一只鳥在另一只鳥的翼尖周圍飛行，它可以從上升的空氣中獲得提升（_），因此在空氣中停留所需的能量更少。

除了“自由飛行”策略外，科學家們還驚訝地發現，遷徙的鳥類會調整翅膀拍打的時間，并以非常精確的方式調整它們的位置，以最大限度地提高升力，同時避開空氣向下移動的區域。

首席研究員史蒂文·葡萄牙告訴英國廣播公司：“他們能夠感覺到前方的鳥在做什么，這里的‘好空氣’來自哪里，現在如何將自己完美地安置在那里?！?/span>

事實上，“V”形構造一直被認為可以幫助鳥類更有效地飛行。先前的一項研究表明，當鳥類以“V”字形飛行時，它們的心率會下降。噴氣式戰斗機也被發現能夠通過靠近其他噴氣式戰斗機的翼尖減少高達18%的能源消耗。這兩個發現都讓科學家們懷疑“V”形形成有一個有效的目的，但直到現在他們仍然缺乏證據。

對于科學家來說，這項新的研究提供了一種對有趣的自然現象的洞察。但葡萄牙表示，這對航空公司來說可能意味著更多——幫助他們了解如何通過飛機編隊來模仿這一點，以節省燃料。”