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对自然的认识是一个不断修正和完善的过程。请阅读以下材料,回答问题:

材料一:2400多年前古希腊学者亚里士多德提出,植物生长发育所需的物质全部来自土壤;

材料二:17世纪,比利时海尔蒙特把一棵2.5千克的柳树种在装有90千克泥土的木桶里,

只浇水。经过五年,再次称重,柳树质量已达80多千克,而泥土减少却不到100克,

材料三:18世纪,英国普利斯特利通过如图乙实验发现,A钟罩内的小鼠很快死亡,B钟罩内的小鼠却可活较长时间。

材料四:1864年,德国萨克斯发现绿色植物在光下还能合成淀粉等物质。1897年,人们首次把绿色植物的上述生理现象称为光合作用。

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    “Daily Star, sir” called Jason, carrying some newspapers under his arm. The little boy had been running up and down the street, but there were still twenty1 left. His voice was almost gone and his heart was 2. The shops would soon close, and all the people would go home. He would have to go home too, carrying the papers3money. He had hoped to sell more papers tonight to make more money to buy a 4for his mother and some seeds for his bird. That was why he had bought the papers with all his money. He 5as he thought of his failure to sell all his papers.

    “You don't know the 6 of selling papers. You must shout, “Hot news! Bomb bursting!” another newsboy Chad told Jason. “7 it's not in the paper at all,” replied Jason. “Just run away quickly 8 they have time to see, and you'll 9 out and get your money,”Chad said.

    It was a new 10 to Jason. He thought of his bird with no11 and the cake he wanted to buy for his mother, but was12 that he would not tell a lie. Though he was13a poor newsboy, he had been 14 some good things.

    The next afternoon Jason went to the office for his papers15 .Several boys were crowding around Chad, who declared with a 16 smile that he sold six dozen the day before. He added that Jason 17 money because he would not tell a lie. The boy 18 at Jason. “You wouldn't tell a lie yesterday, my boy?” A gentleman at the office came up and patted Jason's shoulder 19 .”You're just the boy I am looking for.” A week later Jason started his new20. He lost sale of twenty papers because he would not tell a lie, but got a well-paid job because he told the truth.