Scientistshavefoundthatmigrating(遷徙)birdsflynotjustingr...

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問題詳情：

Scientists have found that migrating (遷徙) birds fly not just in groups all the time, but in “V” formation and they have also tried to find out what good points birds get from this “V” formation. Now, a research group from the 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 (拍打) its wings, it makes the air move in different directions. Scientists found in the study that the air creates an upward-moving wave at the tips of the wings (翼尖), which means that if a bird flies around the wingtips of another bird, it can get some help from the rising air and then they can use less energy to stay in the air.

But there is a small problem – the lead bird gets no lift advantage and can easily get tired. This is why a group of migrating birds change their leaders from time to time, according to The New York Times.

Scientists were also surprised to see that migrating birds timed their wing beats and changed their places in a very simple way to make the most of the lifting effect while avoiding areas where the air moved downward.

“They’re able to sense what’s going on from the bird in front, where this ‘good air’ is coming from and how to help themselves perfectly in it,” lead researcher Steven Portugal told BBC.

In fact, the “V” formation has long been thought to help birds fly more efficiently (有效地) without wasting too much energy. Jet fighters (戰鬥機) were also found to be able to reduce their energy use by up to 18% by staying near the wingtips of other Jet fighters. Both of these findings led scientists to wonder that the “V” formation had an efficiency purpose, but until now they still don’t have enough facts to show what they are thinking about is really true.

“For scientists, the new study provides an insight into an interesting natural thing. But it could mean even more for airplane companies – helping them understand how they can imitate that with their plane formations to save energy,” said Portugal.

1. According to the new study, when birds migrate, ______.

A. they don’t often change their lead birds

B. they fly in “V” formation to make best use of lift

C. they fly in “V” formation to protect the birds behind

D. the air around them makes it hard for the lead bird to fly fast

2. What is the importance of the new study according to the article?

A. It suggests that the “V” formation can help planes fly faster.

B. It has led scientists to study more about different kinds of birds.

C. It might help airplane companies to think of ways to save energy.

D. It shows that the jet fighters form the best shape of a “V” formation.

3. The underlined word “imitate” in the last paragraph probably means “______”.

A. use B. change C. learn D. copy