六级冲刺备考的改错练习（8）

　　第八篇： Error Correction

　　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.

　　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 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 quite fantastically but, with --80.

　　the rapid development of moderns technology, who