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三门峡水利枢纽是新中国第一个大型水利工程,也是新中国治理黄河的第一个大型工程。读咸阳—潼关河段纵坡剖面示意图,回答下列各题。

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    My father was a foreman of a sugar-cane plantation in Rio Piedras, Puerto Rico. My first job was to drive the oxen that ploughed the cane fields. I would walk behind an ox, guiding him with a broomstick. For $1 a day, I worked eight hours straight, with no food breaks.

    It was very tedious work, but it prepared me for life and taught me many lasting lessons. Because the plantation owners were always watching us, I had to be on time every day and work as hard as I could. I've never been late for any job since. I also learned about being respectful and faithful to the people you work for. More importantly, I earned my pay; it never entered my mind to say I was sick just because I didn't want to work.

    I was only six years old, but I was doing a man's job. Our family needed every dollar we could make because my father never earned more than $18 a week. Our home was a three-roomed wood shack with a dirty floor and no toilet. Nothing made me prouder than bringing home money to help my mother, father, two brothers and three sisters. This gave me self-esteem(自尊心), one of the most important things a person can have.

    When I was seven, I got work at a golf course near our house. My job was to stand down the fairway and spot the balls as they landed, so the golfers could find them. Losing a ball meant you were fired, so I never missed one. Some nights I would lie in bed and dreamt of making thousands of dollars by playing golf and being able to buy a bicycle.

    The more I dreamt, the more I thought. Why not? I made my first golf club out of guava limb(番石榴树枝) and a piece of pipe. Then I hammered an empty tin can into the shape of a ball. And finally I dug two small holes in the ground and hit the ball back and forth. I practiced with the same devotion and intensity. I learned working in the field—except now I was driving golf balls with a club, not oxen with a broomstick.

同类题3

小明同学想在实验室用NaOH溶液与CO2气体制取Na2CO3溶液。但是经过检验,发现很难得到纯净的Na2CO3溶液,在老师的帮助下查阅了相关资料,制定了计划。
【查阅资料】
①CO2通入NaOH溶液时极易因CO2过量而产生NaHCO3 , 且无明显现象。
   ②NaHCO3溶液煮沸时不会发生分解反应;NaHCO3溶液与CaCl2溶液不反应
   ③NaHCO3+NaOH=Na2CO3+H2O       
④Na2CO3+CaCl2=CaCO3↓+2NaCl
【制取步骤】
①量取两份50 mL相同浓度的NaOH溶液备用;
   ②用一份50 mL NaOH溶液吸收过量的CO2气体,至CO2气体不再溶解;
   ③小心煮沸②溶液1-2分钟;
   ④在得到的③的溶液中加入另一份50 mL NaOH溶液,使其充分混合即得。
【实验探究】制得的Na2CO3溶液中可能含有的杂质是____
为检验制得的溶液是否为纯净的Na2CO3溶液,请你与小明同学一起完成下列实验探究:
实验步骤实验现象实验结论
取少量制得的溶液于试管中,加入过量的显中性的CaCl2溶液____溶液中含有Na2CO3
将上步实验所得混合物进行过滤,将滤液分成两份取其中一份加入足量的____无气泡产生制得的溶液中不含____
取另一份加入____制得的溶液中含NaOH
【结论】所制得的不是纯净的Na2CO3溶液。
【评价与反思】小芳同学认为可以用过量的Ca(OH)2溶液替代CaCl2溶液进行以上实验,你认为是否可行,并说明原因____