2014年英语四级考试模拟试题及答案(第六套)_第4页

　　Directions: In this section, you will hear a passage three times. When the passage is read for the first time, you should listen carefully for its general idea. When the passage is read for the second time, you are required to fill in the blanks numbered from 26 to 39 with the exact words you have just heard. For these blanks, you can either use the exact words you have just heard or write down the main points in your own words. Finally, when the passage is read for the third time, you should check what you have written.

　　Can time travel really be done? Physicists think that travel into future is possible. Einstein’s special theory of (26)________, published in 1905, predicted that time should bi elastic(弹性的), stretching or (27)_______ as an observer moves. To get a really big time leap it is (28)_______ to travel at near the speed of light — 300,000 km per second. At 99% of this speed, a 29)_______ trip to a distant star and back would take 15 months, but travelers would return home to find that nearly nine years had passed on Earth. In (30)_______, you would have leapt several years into Earth’s future.

　　Gravity offers another way to slow time. On the Earth’s (31)______, clocks tick a little slower than on the moon, for example. Near a black hole, gravity is so (32)_______ that time is slowed to a crawl relative to us. These facts are accepted by almost all scientists. Traveling forwards in time has been (33)_______ convincingly in experiments, but the possibility of traveling when a physicist named Stockhum investgated what might happen to an observer who orbits a rapidly spinning cylinder. He showed it was(34)_______ to travel in a closed loop and return to your starting point before you left.

　　Worm holes are similar to black holes, but there exists a key difference. Whereas black holes offer a one-way (35)______ to nowhere—fall in and you never get out worm holes have an exit as well a3 an entrance. To find whether such an idea can be taken seriously, scientists at California Institute of Technology investigated what it would take for such a short cut though space to exist. They found that if you tried to make a worm hole out Of any normal form Of matter，it would (36)_____under its own gravity and turn into a black hole.

　　For a worm hole to remain stable, it would have to be made of exotic material that would create an anti-gravity force.

　　Keys

　　1.A 2.C 3.A 4.B 5.B 6.A 7. C 8. C 9. C

　　10.A 11.A 12.D 13.B 14.B 15.D 16. C 17. B 18. D

　　19.A 20.C 21.B 22.D 23.A 24.B 25. A

　　26.relativity 27.shrink/rig 28.necessary 29.rocket

　　30.effect 31.surface 32.intense 33.demonstrated

　　34.possible

　　35.journey

　　36.collapse