湖南卫视电视台要播出一部48集电视连续剧,若要每天安排播出的集数互不相同,则该电视连续剧最多可以播出几天?
解:如果要求每天安排播出的集数互不相等,按照1、2、3、4、5、6、7、8、9集的顺序排下来,
共播了:1+2+3+4+5+6+7+8+9=45(集),
为了集数互不相同,剩余的两集不能单独播一天了,只能分别排在第8天和第9天或最后一天,
即每天按照1、2、3、4、5、6、7、9、11或1、2、3、4、5、6、7、8、12集来播.
所以就是9天;
答:该电视连续剧最多可以播出9天.
现有一生活污水净化处理系统,处理流程为“厌氧沉淀池→曝光池→兼氧池→植物池”,其中植物池中生活着水生植物、昆虫、鱼类、蛙类等生物.污水经净化处理后,可用于浇灌绿地.回答问题:
(1)污水流经厌氧沉淀池.曝气池和兼氧池后得到初步净化.在这个过程中,微生物通过____ 呼吸将有机物分解.
(2)植物池中,水生植物、昆虫、鱼类、蛙类和底泥中的微生物共同组成了____ (生态系统、群落、种群).在植物池的食物网中,植物位于第____ 营养级.植物池中所有蛙类获得的能量最终来源于____ 所固定的____ 能.
(3)生态工程所遵循的基本原理有整体性、协调与平衡、____ 和____ 等原理
(4)一般来说,生态工程的主要任务是对____ 进行修复,对造成环境污染和破坏的生产方式进行改善,并提高生态系统的生产力.
短文改错
One day, little Tony went to a shopping center with his parent. It was very crowded. Tony saw a toy on a shop window. He liked it so very much that he quickly walked into the shop. After looks at the toy for some time, he turned around and found where his parents were missing. Tony was scared and begun to cry. A woman saw him crying and telling him to wait outside a shop. Five minutes later, Tony saw parents. Mom said, “How nice to see you again! Dad and I were terrible worried.” Tony promised her that this would never happen again.