下列各句中，没有语病的一句是(　　)

在图中所示的电路中，电源电压为12伏且保持不变，电阻R₁的阻值为10欧，滑动变阻器R₂上标有“50Ω  2Α”字样。闭合电键S后，电路中的电流为0.3安。

① 求电阻R₁两端的电压U₁。
② 求此时变阻器R₂连入电路中的电阻。
③ 移动变阻器的滑片P，使电流表示数的变化量最大，并求出电流表示数的最大变化量DI。

关于电热的下列几个说法，错误的是

阅读理解

    Every evening, 15-year-old Rashida returns home from school,changes out of her uniform, and rushes to a neighboring farm to help her motherharvest vegetables. Her father is disabled, so the modest profit the two ofthem earn must cover food, clothing and other necessities for all sevenchildren and their parents. Despite having precious little time to study,Rashida is one of the top students at her junior secondary school. But with somuch responsibility on her small shoulders, she admits that it is sometimeshard for her to imagine a more promising future.

    Last year, Rashida was invited to join 155 other girls at CamfedGhana's first Girls' Career Camp, a program designed to inspire girls growingup in the country’s Northern Region to dream big, and to support them to pursuethose dreams. “We organized this camp because we wanted to let girls know thateven if they are struggling with poverty, their lives will not be defined bylimitations,” says Dolores Dickson, Camfed Ghana’s Executive Director.

    Over the course of five days, the camp led the junior andsecondary school students through a range of experiences and career opportunities that were entirely new to them. Dr. Agnes Apusiga, a lecturer from the University of DevelopmentStudies, ran the workshop on goal-setting and career choices, describing theuniversities and training colleges in Ghana that could help them achieve theirdreams. Participants then visited the University for Development Studies, wherethey toured the medical school and science labs. Another highlight was aworkshop at the computer lab at Tamale Secondary School. Many of the girls hadstudied information technology from a book but had never before seen acomputer.

   “When the girls arrived at camp, they were not ambitious,because they didn't have any idea what the world held for them,” says EugeniaAyagiba, Project Officer with Camfed Ghana. “Many had scarcely traveled beyondtheir own villages.”

   “I think the most important thing that happened at the camp isthat we opened a window of hope for a group of girls coming from backgrounds ofpoverty,” says Eugenia. For Rashida, who has been laughed at in the past by herschoolmates because of her father's disability, the experience was important.“She told one of the camp mentors(辅导员) that whenshe is at school, she often feels like a misfit, and she prefers to keep toherself,” says Eugenia. “But at the camp, it was different. She made friendswith girls who have similar struggles. She took part in every single activity,every single game. On the last day, she said to her mentor, ‘The camp haschallenged me to study hard. Now I see that there is light at the end of thetunnel.’

读书深入思考，通达真相、真理、真谛。下图是小明读过的众书中一本，该书讲述的事件发生在（   ）