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Back in July 1965, the Mariner Four Space Probe transmitted the first close - up pictures of Mars and convinced many people that Mars was as dead as our own moon. Two later space probes seemed to confirm this.
But then, in 1971, Mariner Nine raise hopes once again that there could be life on the planet--or at least that life might once have existed there. The range of experiments to be conducted were designed by mission scientists such as Chuck Klein:
"It was like shooting blind, so to speak, to be trying to devise experiments to look for evidence of life. And we decide to try to use an instrument which could incorporate many different assumptions about what Martian biology might be like--what the bugs might be like or not like. But the fundamental proposition in each portion of our experiment was to look, over a period of time, for evidence of some process going on which we could attribute to biology."
The scientists controlled the Viking experiments from a distance of almost 100 million kilometers. Cameras took pictures of the area a round the robot landers--in case anything moved into view. No aliens were spotted by the cameras, but other experiments seems to show signs of life.
"Almost everything that we planned began to give us data of some kind--that is to say, it wash’ t like everything was dead. For many weeks, We were goaded by the media, who were terribly excited--they were constantly looking for a headline, you know, ’ .They Found Life ! They Found Life ! Every bit of information that we came up with was squeezed by them to try to put a positive twist on it... We really had to work very hard to maintain our cool and present the data just the way we saw it."
But these apparent signs of life were deceptive. By repeating the experiments and double checking the results, the scientists eventually came to the conclusion that the whole planet was dead and would, in fact, be deadly to living organisms.
Since 1976, there have been no further visits. A probe sent by NASA exploded before reaching the planet last year and it now doesn’ t look as if there’ ll be another Mars visit until the end of the decade.
When we do get back there, will we find something new And what about us Could we ever live on Mars This isn’ t as strange an idea as it sounds according to astronomer Patrick Moorer:
"It’ s fair to say that, from a technical point of view, we could put men on Mars within the next few decades. Whether we actually do so or not depends very much more upon politics and finance than upon sheer science, but I think it could be done. And I’ m quite prepared to believe that by this time in the next century, there will be flourishing colonies upon Mars."

Which of the following is closest in meaning to the sentence "It was shooting blind.., to look for evidence of life..."（）

A:We were carrying on experiments aimlessly. B:It was impossible to reach the Mars because of the distance. C:We could see nothing in the outer space. D:We didn't believe life really existed on Mars.

“Two centuries ago, Meriwether Lewis and William Clark left St. Lois to explore the new lands acquired in the Louisiana Purchase,” George W. Bush said, announcing his desire for a program to send men and women to Mars. “They made that journey in the spirit of discovery... America has ventured forth into space for the same reasons.”
Yet there are vital differences between Lewis and Clark’s expedition and a Mars mission. First, Lewis and Clark were headed to a place amenable to life; hundreds of thousands of people were already living there. Second, Lewis and Clark were certain to discover places and things of immediate value to the new nation. Third, the Lewis and Clark venture cost next to nothing by today’s standards. In 1989 NASA estimated that a people-to-Mars program would cost $ 400 billion, which inflates to $ 600 billion today. But the fact that a destination is tantalizing does not mean the journey makes sense, even considering the human calling to explore. And Mars as a destination for people makes absolutely no sense with current technology.
Present systems for getting from Earth’s surface to low-Earth orbit are so fantastically expensive that merely launching the 1,000 tons or so of spacecraft and equipment a Mars mission would require could be accomplished only by cutting health-care benefits, education spending or other important programs or by raising taxes. Absent some remarkable discovery, astronauts, geologists and biologists once on Mars could do little more than analyze rocks and feel awestruck beholding the sky of another world.
It is interesting to note that when President Bush unveiled his proposal, he listed these recent major achievements of space exploration: pictures of the rings of Saturn and the outer planets, evidence of water on Mars and the moon of Jupiter, discovery of more than 100 planets outside our solar system and study of the soil of Mars. All these accomplishments came from automated probes or automated space telescopes. Bush’s proposal, which calls for “reprogramming” some of NASA’s present budget into the Mars effort, might actually lead to a reduction in such unmanned science, the one aspect of space exploration that’s working really well.
Rather than spend hundreds of billions of dollars to hurl tons toward Mars using current technology, why not take a decade or two decades, or however much time is required researching new launch systems and advanced propulsion If new launch systems could put weight into orbit affordably, and if advanced propulsion could speed up that long, slow transit to Mars, then the dreams of stepping onto the Red Planet might become reality. Mars will still be there when the technology is ready.
The drive to explore is part of what makes us human, and exploration of the past has led to unexpected glories. Dreams must be tempered by realism, however. For the moment, going to Mars is hopelessly unrealistic.
According to the author, once on Mars, astronauts, geologists and biologists

A:could not make any remarkable discovery. B:could only analyze the rocks there in detail. C:could not find the mysteries of life in solar system. D:could well understand the operation of the whole solar system.

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According to the author, once on Mars, astronauts, geologists and biologists

A:could not make any remarkable discovery. B:could only analyze the rocks there in detail. C:could not find the mysteries of life in solar system. D:could well understand the operation of the whole solar system.

Text 2 After a shaky start, the Martian flotilla that has arrived over the past few weeks is getting down to business. Two of the five craft in it seem to be working perfectly. Two are lost. And a fifth is sick, but undergoing treatment. The most spectacular pictures so far have been provided by Mars Express, the European Space Agency’s contribution to the fleet. On January 28th this reached its final working orbit (which takes it over both poles, and thus allows it to see the whole of Mars over the course of a few days as the planet revolves beneath it). It has, however, been sending back data since shortly after it arrived, and a few days ago its controllers released a series of beautiful photographs, including a stereo image of Valles Marineris, a huge canyon that may have been formed by flowing water. The most scientifically significant result, though, has come from Opportunity, America’s second Mars rover. One of Opportunity’s cameras has photographed evidence of stratification in nearby rocks. Such stratification indicates that the rocks concerned are sedimentary. The layers could be repeated wind-blown deposits, or consist of ash from successive volcanic eruptions. But the terrestrial rocks they most resemble are ones that have formed under water. The reason everyone is getting so excited is because there is a widespread assumption that any form of life which might dwell on Mars would need liquid water to live—or, even if it could now subsist by extracting moisture from ice, would have needed liquid water to evolve to that stage. Mars has seen more probes launched towards it than all of the other planets put together precisely because of this hope that it might harbour life. So there is a lot riding on the answer—not least the funding of future missions. Besides its scientific significance, the success of Opportunity has also helped to distract attention from the sudden refusal of Spirit, the first American rover to arrive on Mars, to talk to its controllers. This craft had tentatively, but successfully, nosed its way off its landing platform, and was about to drill its way into a nearby rock prior to doing a spot of chemical analysis, when it went silent. However, the engineers at NASA, America’s space agency, are nothing if not resourceful, and they have a good record of carrying out running repairs on spacecraft that are millions of kilometres away. In the case of Spirit, they think that one of the craft’s memory chips has got cluttered up with files created on the journey to Mars. That caused another chip, which manages the first, to throw a wobbly and to keep rebooting the computer. They are currently testing this idea by loading a diagnostic program on to the computer. In addition, as a precaution, they have deleted excess files from the equivalent memory chip on Opportunity. Spirit’s spirits may thus revive. As to the failures, the Japanese abandoned their fly-by craft Nozomi in December, and the British team in charge of Beagle 2, which is presumed to have landed on December 25th but from which no signal has been received, also seems to have called it quits. Still, a 40460% success rate (depending on whether Spirit is brought back into commission) is not bad by the historical standards of missions to Mars. Now, the real science begins.

We can learn from the passage that people's enthusiasm for Mars（）

A:could subsist despite the discovery of ice B:is aroused by the wish to find life there C:depends largely on the funding of these projects D:might turn out to be a waste of resources

Passage Two
Thousands of years ago, in the middle of an ocean, miles from the nearest island, an undersea volcano(火山) broke out. The hot liquid rock piled higher and higher and spread wider and wider. In this way, an island rose up in the sea.
As time went on, hot sun and cool rains made the rock split and break to pieces. Sea waves dashed against the rock. In this way, soil and sand came into being.
Nothing lived on the naked soil. And then the wind and birds brought plant seeds, spiders and other little creatures there. Only plants could grow first. Only they, in sunlight, could produce food from the minerals of the soil, water and air. While many animals landed on the island, they could find no food. A spider spun its web in vain, because there were no insects for its web to catch, In sects couldn’ t stay until there were plants for them to eat. So plants had to be the pioneer life on this new island.

According to the passage, which of the following is true（）

A:Spiders were the first life that could live on the island. B:The island is far away from any piece of land. C:Insects could not live on the island without plants. D:Plants were brought to the island by human beings.

Passage Two Thousands of years ago, in the middle of an ocean, miles from the nearest island, an undersea volcano(火山) broke out. The hot liquid rock piled higher and higher and spread wider and wider. In this way, an island rose up in the sea. As time went on, hot sun and cool rains made the rock split and break to pieces. Sea waves dashed against the rock. In this way, soil and sand came into being. Nothing lived on the naked soil. And then the wind and birds brought plant seeds, spiders and other little creatures there. Only plants could grow first. Only they, in sunlight, could produce food from the minerals of the soil, water and air. While many animals landed on the island, they could find no food. A spider spun its web in vain, because there were no insects for its web to catch, In sects couldn’ t stay until there were plants for them to eat. So plants had to be the pioneer life on this new island.

According to the passage, which of the following is true（）

A:Spiders were the first life that could live on the island. B:The island is far away from any piece of land. C:Insects could not live on the island without plants. D:Plants were brought to the island by human beings.

There could be life on the Mars in the future if ______.

A:it supported life in the past B:certain gases are used to cool the planet C:the atmosphere can be heated enough to grow simple plants D:the planet’s volcanoes become as active as they were in the past

Many scientists today are convinced that life exists elsewhere in the universe-life probably much like that on our own planet. They reason in the following way.
As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.
Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.
Finally, life could evolve only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.
If we suppose that every star in the universe has a family of planets, then how many planets might support life First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.
This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.
At the end of the passage the author suggests that ______.

A:it is impossible for life to exist on planets B:earthlike life could only exist on a few planets C:life could exist on only one planet in a million D:life could exist on a great number of planets