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Scientists believe that conditions on Mars around 3.8 billion years ago were very similar to those of the early earth, when primitive organisms were spreading through our oceans. At that time, Mars would have been much warmer and wetter than it is today, with an atmosphere composed mainly of carbon dioxide, just like that of the earth at the time. Under these conditions, it is highly probable that life may have arisen on Mars as well.

But, even if life did not arise naturally on Mars, it does not mean that it could not have existed there. According to Professor Paul Davies of the University of Adelaide, Australia, life forms could have been transferred between the earth and Mars in wreckage (broke pieces) created by the impact of comet(彗星) and small planets on the surface of the two planets.

Even today, about 500 tons of material from Mars lands on earth every year. It is mainly in the form of the dust but occasionally a larger chunk(厚片，大块) strikes the earth. In 1911, a piece of Martian rock crashed in Egypt, killing a dog. According to Professor Davies, it is in these chunks of rock, which were much larger and more frequent in the past that life forms could have been transported from planet to planet.

“But how could these life forms have survived their journey through space?” says Paul Davies, “The difficulty in believing this theory is that a bacterium on its own in space has to struggle itself not only against cold but also against deadly cosmic (宇宙的) radiation. But wrapped in a rock the situation is different. A rock ten meters across would shield life inside it from a lot of radiation and the temperature might only be minus 10 or 20 degrees, the sort of thing we have on earth.”

小题1:Where do some scientists suppose life probably come from? (3’) (No more than 6 words)

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小题2:What does Professor Paul Davies believe? (3’) (No more than 6 words)

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小题3:Why could life survive when transferred from one planet to another? (3’) (No more than 12 words)

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小题4:According to Professor Paul Davies, how did the wreckage come into being? (3’) (No more than 10 words)

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小题5:List at least two differences about Mars between the past and now. (3’) (No more than 16 words)

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资料：
(1)某工业企业大量生产A、B两种产品。生产分为两个步骤，分别由第一第二两个车间进行。第一车间是机加工(包括设备调整作业、加工作业、检验作业、车间管理作业)，第一车间为第二车间提供半成品，第二车间为组装(包括组装、检验、包装、车间管理作业等)，第二车间将半成品组装成为产成品。该厂为了加强成本管理，采用逐步结转分步法按照生产步骤(车间)计算产品成本，各步骤在产品的完工程度为本步骤的50%，材料在生产开始时一次投入，该企业不设半成品库，一车间完工半成品直接交由二车间组装。各车间7月份有关产品产量的资料如下表所示：

按实际作业成本分配率分配作业成本，计算填列一车间A和B的成本计算单。