题目

如图所示电路用的是等效替代法测量未知电阻阻值． 其中Rx是待测电阻（阻值大约几百欧），R是滑动变阻器，R0是电阻箱（电阻箱的最大电阻值大于Rx），请根据实验电路图把下列主要实验步骤中的空白填齐． （1）按电路图连好电路，并将电阻箱R0的阻值调至最大． （2）只闭合开关S1和 ，调节滑片P，使电流表指针指在适当的位置，记下此时电流表的示数为I． （3）只闭合开关S1和 ，同时调节 （选填“滑动变阻器”或“电阻箱”），使电流表的示 阅读理解 　　A senior United Nations Children’s Fund(UNICEF)official on May 29 praised China for its remarkable achievements in children’s welfare(福利)．A．H．M．Farook, UNICEEF’s operations area officer for China and Mongolia said that China“can be very satisfied to tell the whole world what can be done with limited resources to help its children to grow healthily and happily．” 　　China’s child population makes up one-fifth of the world’s total．“The reason behind the tremendous(巨大的)achievement is China’s long tradition of caring for children both at home and in society,”he said． 　　“What’s more is that Chinese people have always given special attention to children who are in special need．”The UN official made the remarks when addressing a group of 50 children and staff from the Beijing Children’s Welfare Home at the Shangrila Hotel, Beijing． 　　The hotel invited the orphans to share snacks(小吃), sing, dance and play games at a park inside the hotel for a“Share the Sunshine”party, as a prelude(前奏)to celebrations to mark the Children’s Day． 　　The Beijing children’s Welfare Home, set up soon after New China was founded in 1949, has at present more than 400 children． 　　A leading official of the welfare institution said that the children live a happy life and that the agency(机构)spends 400－500 yuan a month for an average orphan．An average Chinese workers earned 440 yuan a month during the first quarter this year． 　　Gu Xiaojin, deputy secretary-general of the China Youth Development Foundation(CYDF), said people from all walks of life have contributed to the welfare of the Chinese children． 　　She said that CYDF set up the Project Hope in 1989, which calls on people across the country to donate money to help poor children to continue their schooling． 　　By the end of last year, she said, CYDF had collected nearly 700 million yuan in donations, which has helped the establishment(建立)of 2,074 Hope primary schools and enabled more than 1.25 million dropouts to return to school classrooms． 　　Three“Hope Stars”also attended the party．They were model teenagers chosen among students who are economically supported by the Project Hope to further their nine-year compulsory(义务)studies in the poverty-stricken regions．They will be torchbearers(火炬接力者)for the Chinese Team for the up coming Atlanta Olympic Games this year． (1) Children can grow healthily and happily as long as ________． [　　] A． parents take good care of them both at home and in society B． the whole society care for children as well as their parents C． School and teacher pay much attention to the growth of children D． Chinese people always pay much attention to children who are in special need (2) Every year the Beijing Children’s Welfare Home spends ________ on the orphans． [　　] A． 1,920,000 yuan B． 2,160,000 yuan C． Over 2,400,000 yuan D． 2,200,000 yuan or so (3) CYDF collected 700 million yuan with the purpose of ________． [　　] A． reducing dropouts B． helping homeless orphans C． supporting the Chinese Team for the coming Atlanta Olympic Games D． establishing 2,074 Hope primary schools all over the country (4) We can infer from the text that ________． [　　] A． every Chinese child has its own special need, so we should pay special attention to each B． all the children in the poverty-stricken regions of China are too poor to go to school C． ever since liberation, the Chinese Communist Party has been concerned(关心)about the growth of the younger generation D． with the help of UNICF officials, there are no more dropouts in China