2．What can be inferred from the passage about biological clocks?
A．They are used by all plants and animals to tell time．
B．Pigeons’biological clocks are regulated every day with the sunrise．
C．The built-in biological clocks cannot be changed．
D．They gradually developed as pigeons grow mature．
3．How can people shift pigeons’ biological clocks?
A．By training them when they are young．
B．By minor and harmless operations．
C．By taking them really far away from home．
D．By keeping them in artificial days．
4．Which is true about pigeons’ finding directions?
A．With a brass on back they can find directions sooner．
B．They can find directions better than other birds．
C．They use the earth’s magnetic field and the sun to find directions．
D．They can find directions only to their home．
5．What does the author want to say by citing the last experiment?
A．On heavily cloudy days，pigeons that are not well trained do not fly.
B．Pigeons use different sources to find directions on different weather.
C．Magnetic field is an important source in helping pigeons to find directions.
D．The little magnet bars make it easier for pigeons to find directions．
Passage Two
In some ways,yes—but the differences matter more．Just as human history has been shaped by the rise and fall of successive empires，the computer industry has, in the few decades of its existence，been dominated by one large company after another．During the mainframe era，IBM wore the crown．But it fumbled the transition to smaller machines in the personal-computer era，and the throne was usurped by Microsoft．Now，at the dawn of the new era of Internet services，Google is widely seen as the heir to the kingdom．As the upstart has matured into a powerful industry giant，the suggestion that “Google is the new Microsoft ”has become commonplace in computing circles．Is it true?
The comparison is both a compliment and a reproach．It is a compliment because it implies that Google has now become the company that defines the environment in which other technology firms operate，just as IBM and Microsoft once did．As with Microsoft in its heyday，Google is the technology firm where the smartest geeks aspire to work；it embodies the technological zeitgeist；and it is a highly regarded company that has become a household name．But the comparison is also a reproach，because it highlights growing concern that Google is now too powerful for its own good，or that of the industry，or indeed that of the world at large．
For many people，Google provides the front door to the Internet．For many online businesses,their position in its search ranking—the workings of which are a closely guarded secret—is a matter of life or death．Too much power is thus concentrated in Google’s hands，say critics，including Microsoft’s Bill Gates．Microsoft and other big Internet firms，including eBay，Amazon and Yahoo，are now said to be negotiating various alliances in order to provide a counterweight to the new behemoth．Smaller firms feel even more vulnerable．As soon as Google says it is moving into a particular market，small fry in that market now dart for cover，unless they are lucky enough to be acquired by Google． |
