20. According to the passage, winners _____.

A. deal with problems rather than blame others

B. meet with fewer difficulties in their byes

C. have responsible and able colleagues

D. blame themselves rather than others

21. When problems occur, winners take them as _____.

A. excuses for their failures

B. barriers to greater power

C. challenges to their colleagues

D. chances for self-development

22. Which of the following is the best title for the passage?

A. A Winner's Secret.

B. A Winner's Problem.

C. A Winner's Opportunity.

D. A Winner's Achievement.

　　If you could travel in time, where would you go? Perhaps you would watch an original performance of a Shakespeare's play in Elizabethan England? What about hanging out with

Laozi in the Spring and Autumn Period? Or maybe you'd voyage far ahead of the present day to see

what the future holds.

　　The possibility of time travel is indeed appealing. Stories exploring the subject have been around for hundreds of years. Perhaps the best known example is science fiction novel The Time Machine, which was written by H.G.Wells and published in 1895 for the first time. It was adapted

into at least two feature films of the same name, as well as two television versions, and a large number of comic book adaptations. It is generally credited with the popularization of the concept of

time travel using a vehicle that allows an operator to travel purposefully and selectively. The term "time machine", coined by

Wells, is now universally used to refer to a vehicle transporting people into the far future.

But could time travel actually be possible? Some scientists say yes, in theory. They propose

using cracks in time and space called"wormholes",which could be used as shortcuts to other

periods．Einstein's theory of relativity allows time travel in extreme circumstances. And British

physicist Stephen Hawking says you could travel into the future with a really fast spaceship-going

at nearly the speed of light. Though building such a spaceship would of course be no simple task．