题目

某淡水湖泊生态系统因为N、P元素等无机污染引起了藻类的大量繁殖，研究人员拟采用生物控制技术进行防治，对该生态系统的有机碳生产率及能量流动进行了研究，结果如下图所示。分析回答下列问题。 （1）研究时，检验水样中的所有生物可看作微型_________。图甲显示：5、7月份0.2 m处有机碳的生产量很高，但0.6 m以下水深有机碳生产率较低，主要原因是__________________。（2）在资源不受限制的理想条件下，某生物种群每两年增加50%，若初始数量为300028、  You and your parents can stop worrying- Edison, Pasteur, Darwin and many others were far from being "bright boys " when they were under twenty. Some of them, in the eyes of their teachers, were day- dreamers or slow pupils. So, young men or women, if you have the same experience, don' t fed disappointed. It is always the case that parents prefer giving mere inspiring examples to encourage their children. If you take piano lessons and are not practicing hard, your parents might justly complain and show you the famous picture of little Mozart in his night- shirt, playing the piano at midnight. But the fact is that he didn’t appear to have much talent(才干)for music when he was quite young. It was not until 22 that Mozart suddenly became fired with a great liking(爱好)for music. In the sciences, there have been thousands of people who showed great interest in certain subjects from their earliest years, and hundreds who had no idea of what they would do in the future. The well-known French chemist Pasteur displeased his parents because Louris did nothing but drew pictures and went fishing. Pasteur was twenty years old before he showed any interest in science. You have the Wright brothers, who showed great talent in engineering when they were quite young. And you have Thomas Edi-son, whose teacher tried to get him out of the class because his brain was often confused. You have the Nobel Prize Physicist Enrico Fermi, who at 17, had read enough mathematics for a doctor's degree. But there is also Charles Darwin, who hated to go to school when he was young. His farther was once so angry and shouted, "You care for nothing but shooting dogs and rat - catching. You will put your parents to shame." So who knows what might happen in the future? It is, of course, better for the young people to know what they want to do in life . But they needn’t despair if they don ' t . There is still plenty of time and it’s never too later for success. 1. Before the age of 20, Pasture, Darwin and Edison__________. A. were very interested in their future work . B. were far from showing their talents . C. showed early promise(有成功的希望) D. failed in school. 2. To encourage their children parents are likely to give them__________ A. very excited examples         B. real examples C. some false examples           D. extremely(非常) good examples 3. At the age of 22 Mozart________ A. was accidentally wounded by a fire  B. suddenly become a great musician C. started to play the piano at midnight   D. became greatly interested in music 4. Which of the following statements best expresses the main idea of the passage? A. Most successful adults are failures before the age of 22. B. Early schooling is not important for later success. C. People who show no signs of great talent when they are young might turn out to be greatly successful as adults. D. People who show signs of great success when they are young might turn out to be failures as adults. 5. Young people should not despair (丧失信心) if they are not successful because________.      A. Edison and Darwin were not bright when young      B. they have more years to live than adults      C. they still have a lot of time to work for it      D. no one can tell what might happen in the future