Suppose the space traveler had left at the age of 30, leaving behind a twin brother also aged 30. When he returned he would be 32, but his stay-at-home twin brother would be 60. That is why the “clock paradox”， is sometimes called the “twin paradox”。
Of course it takes quite a long while to accelerate to a high speed, and a long while to make a turn and head back again, so conditions aren’t quite as clearcut as just described。
1.The giant, spherical spaceship mentioned in the passage is。
［A］the outer space［B］a man-made spaceship
［C］the planet Earth［D］the Star Wars mother-ship
2.Some persons have traveled into outer space after conqueringwithin the past 25 years。
［A］the universe［B］Earth’s gravity
［C］the earth ［D］outer space
3.We have explored or sent robot spaceships to the following space except。
［A］the moon［B］Venus［C］Jupiter［D］Mars
4.Why is the conquest of space more than a great adventure?
［A］Because it is full of challenges for human beings。
［B］Because it may be necessary for human beings to survive。
［C］Because it is the greatest adventure in human history。
［D］Because it is more exciting than any other adventures。
5.The moon and the asteroids are alike with respect to their 。
［A］size and moving ways ［B］comfortable living conditions
［C］rich and valuable metals［D］solar energy
6.Why can’t ultraviolet light scorch our skin on Earth as seriously as it does in space places?
［A］Because the Earth’s atmosphere can make ultraviolet light less harmful。
［B］Because ultraviolet can’t reach the Earth at all。
［C］Because the Earth is far away from those planets radiating ultraviolet light。
［D］Because other space places is near from those planets radiating ultraviolet light。
7.In spite of many risks, scientists will finally buildin space suitable for humans to live。
［A］an environment without ultraviolet light
［B］a lot of homes
［C］an Earth-like environment
［D］an environment with atmosphere
8.The reason some metal alloys can’t be made on Earth is that the heavier metals ___________together with the lighter ones。
9.In space, there is no atmosphere to filter out the sun’s energy. There is plenty of solar energy to be turned into_____________ , for creating comfortable living conditions。
10.According to the author,__________________ will be caused to a man in gravity-free space |
