题干

小丽通过实验测量小灯泡L的电功率,她按图所示的电路图连接好电路,选用的电源电压为3V且保持不变.闭合开关S,发现电流表无示数,而电压表的示数接近3V,由此判断电路出现的故障可能是(   )

A:滑动变阻器短路

B:滑动变阻器断路

C:小灯泡L断路

D:小灯泡L短路

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答案(点此获取答案解析)

C

同类题3

阅读理解

    Palema Malhotra and her husband Anil Malhotra have spent the last 25 years buying the waste agricultural land and reforesting it, to return the land to a bio – diverse rainforest for elephants, birds and other creatures.

    The couple owns 300 acres of land in Brahmagiri, India. They have spotted more than 300 kinds of birds as well as many rare and threatened animal species. But, this was not the scene in 1991 when Anil and Pamela came to this part of the country. “When I came here, it was a wasteland. The owner wanted to sell because he couldn't grow coffee or anything else,” says Anil who worked in the real estate(房地产)and restaurant business in the US before moving to India. “For me and Pamela, this was what we were looking for all our life.”

    The couple had a love for nature from their childhood. When the Malhotras came to India, the pollution horrified them. “That was when we decided to do something to reclaim(开垦)the forest in India,” says Anil. “We were not looking for money. Early on, we realized that shortage of fresh water will be a concern for India and the rest of the world. Acquisition, protection and reclamation of forested lands and wildlife habitat, where vital water sources have their origin, is the only way to save ourselves,” explains Anil.

    They sold what they owned in America, bought the first 55 acres and began to grow a forest. Soon they bought the land nearby as well. “Many of the farmers considered their holdings 'wasteland' as very little grew on it and were happy to get money,” says Anil.

    Hunting and poaching(偷猎)was a challenge and often the locals did not understand what this couple was doing, so it required a lot of talking to create awareness. They worked with the forest department to set up camera traps and keep poachers away. “There are times I have fought with poachers,” says Pamela.

同类题4

阅读材料。完成下到要求。

材料:近代中国铁路发展史上的五个阶段

时间

概况

1874—1889

清朝封疆大吏为海防、漕运计主张修筑铁路;西方列强无视中国主权,擅自兴建吴淞铁路;清政府一方面赎回并拆毁了吴淞铁路,另一方面又允许了作为运煤工具的唐胥铁路的修建,以及孤悬海外的台湾省铁路的兴筑,并由总理海军事务衙门兼领铁路事亨宜。

1889—1903

清政府宜布兴办铁路,制定了官办铁路、借债筑路的政策,批准设立了中国铁路总公司,芦汉铁路、粤汉铁路、关东铁路、沪宁铁路、津浦铁路相继借债兴筑;同时,西方列强强行在中国修筑东省铁路、胶济铁路、滇越铁路。

1903—1911

清政府颁布《铁路建明章程》、允许华商集股筑路,由此各省铁路公司纷纷创设,修筑有潮汕铁路、津厦铁路、新宁铁路等民办铁路;1911年清政府以铁路干线国有为名,收回铁路修筑权并出让给外国列强。

1912—1928

北洋政府宣布遵守成例,完全取缔民办铁路,继续借债筑路,在其统治期间,年均建成铁路212.4公里,逊于清政府和国民政府时期。

1928—1949

国民党政府在:振兴实业”的旗号下制定了铁道建设计划和中外合资筑路政策,浙赣铁路、粤汉铁路、陇海铁路等重要铁路干线和钱塘江大桥、南京铁路轮渡等重要铁路工程相继建成;日本帝国主义侵华期间,一方面在中国东北和台湾擅自修筑大量铁路,另一方面又在中国关内大肆破坏铁路和利用铁路扩大侵华战争,至(全面)杭战初期,关内铁路23%被毁。

——根据杨勇刚《中国近代铁路史》等整理

从材料中提取两条或两条以上信息。拟定一个论题,并就所拟论题进行简要阐述。(要求:明确写出所拟论题,阐述须有史实依据。)