Who can think of the race between the tortoise and the rabbit when it comes to the greatest races？ Sure， that race only took place in ancient Aesop's mind， but while the great modern races can teach us a lot about commitment， perseverance （毅力） and the virtues of having a rather large engine， "The Tortoise and the Rabbit" may tell us everything about animals and even vehicles on this planet．
In a study published this week， Adrian Bejan， a professor of mechanical engineering， concludes that no one should be surprised that the tortoise wins over the seemingly speedier rabbit． In fact， after analyzing the reported speeds of land-air-and-water-based animals， Bejan concludes that the worlds well-known speedsters are actually among the slowest when their movements are averaged out over the course of a lifetime．
The study builds on Bejan's previous research showing that an animals speed increases with mass regardless of species． And that principle can also be extended to non-living things， like aircraft．
After studying data from historical airplane models， Bajan noted the speed of each model increased with its size， too． That doesn't sound right． What about the modern jet fighter？ How is that relatively small craft not faster than a clumsy large transport plane？
Again， Bejan harks back to the tortoise． That transport plane spends lots of time in the air， moving regularly across long distances． The fighter jet， on the other hand， may fly across the sky occasionally， but-like the rabbit-it's often found resting on the ground．
The slow and steady transport plane wins the marathon of life．
But like so many good stories， Aesop's tale offers even more than a lesson in perseverance．
At one point， the rabbit asks the tortoise how he expects to win a race at such a slow pace．
The tortoise-ever focused-doesn't respond But it's the rabbits own words that provide the moment to reflect on， especially in modem times．
"There is plenty of time to relax，" Until there isn't．



Why is the story "The Tortoise and the Rabbit" mentioned？ ______

A. To warm people not to be proud．
B. To introduce a unique phenomenon．
C. To help put forward the author's idea．
D. To show the importance of perseverance．

What has Bejan proved in his research？ ______

A. Airplanes improve in speed．
B. Speed has nothing to do with size．
C. Speed matters most in the animal world．
D. Animals" speed and mass go hand in hand．

What lesson does the author want to teach us？ ______

A. We shouldn't look down on others
B. We should put our time to good use．
C. Staying focused during races is important．
D. People should often reflect on themselves．

What is the main idea of the passage？ ______

A. Life is just like a race．
B. Nearly all races are the same
C. Quickness is not all advantage in a race．
D. The slow but steady are always winners．