2014年大学英语四级改错练习14

　　Some people, in all seriousness, say that

　　humans will be living in space within the next

　　hundred or so years. Planet Earth will be crowded,

　　dirty and lack of resources. A sort of exodus --71.

　　(移居) of mankind will begin.

　　Spaceships will be assembled so that they

　　revolve around the earth. Some may orbit around

　　Mars. These space stations will be serviced by

　　space buses. We saw the first space bus launch in --72.

　　April 1981. This was "Columbia", it made several --73.

　　orbits around the earth and then returned, landing

　　on a huge dry lake bed in California. "Columbia"

　　will be used again. previous spaceships have

　　been abandoned, only the nose cone being used

　　to bring the crews back to earth. --74.

　　Upon established, each space station will --75.

　　generate its own atmosphere and have its own

　　agriculture. it will need to rotation to provide --76.

　　an artificial gravity; people will be forced inwards --77.

　　from the center by centrifugal(向心的)force.

　　The moon and Mars could become new sources of

　　new materials. Driving through space will no --78.

　　longer need Earth fuel-the energy would come

　　from the sun. This energy would be converted from --79.

　　electricity to work magnetic rockets.

　　That all sounds quiet fantastically but, with --80.

　　the rapid development of modern technology, who

　　knows about what the future holds?

　　答案：

　　71. sort -- short

　　72. launch -- launched

　　73. it -- which

　　74. crews -- crew

　　75. Upon --- Once

　　76. rotation -- rotate

　　77. inward -- outwards

　　78. will -- would

　　79. from -- into

　　80. fantastically -- fantastic