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杨凤芝英语基础训练五
Unit five
Text 1
In May 1989, space shuttle“Atlantis” released in outer space the space probe “Megallan,” which is now onher 15-month and one-billion-kilometer flight to Venus. A new phase in spaceexploration has begun.
The planet Venus is onlyslightly smaller than Earth; it is the only other object in the solar system,in fact, that even comes close to earth’s size. Venus has a similar density, soit is probably made of approximately the same stuff, and it has an atmosphere,complete with clouds. It is also the closest planet to earth, and thus the mostsimilar in distance from the sun. In short, Venus seems to justify itslong-held nickname of “earth’s twin.”
The surface temperature ofVenus reaches some 900F. Added to that is an atmospheric pressure about 90 timesEarth’s: High overhead in the carbon dioxide (CO2) that passes for air is alayer of clouds, perhaps 10 to 20 miles thick, whose little drops consistmostly of sulfuric acid (H2SO4). Water is all but nonexistent.
Born with so manyfundamental similarities to earth, how did Venus get to be so radicallydifferent: It is not just an academic matter. For all its extremes, Venus is avaluable laboratory for researchers studying the weather and climate of earth.It has no earth’s oceans, so the heat transport and other mechanisms aregreatly simplified. In addition, the planet Venus takes 243 earth-days to turnonce on its axis, so incoming heat from the sun is added and distributed at amore leisurely, observable pace.
16. Venus is similar toEarth in ________.
[A] size and density
[B] distance from the sun
[C] having atmosphere(D)
[D] all of the above
17. The greatest value instudying Venus should be to ________.
[A] allow us to visit there
[B] understand Earth better
[C] find a new source ofenergy(B)
[D] promote a new spaceprogram
18. The main idea of thispassage is about ________.
[A] problems of spacetravel
[B] scientific methods inspace exploration
[C] the importance of Venusto Earth(C)
[D] conditions on Venus
