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What is the difference between superconductors and common electrical conductors?
A．Superconductors have much lower electrical resistance than common electrical conductors.
B．Superconductors are more durable than common electrical conductors.
C．Superconductors convert greater amounts of electrical energy into waster heat.
D．Superconductors produce only some waste heat

A.Superconductors
B.
B．Superconductors
C.
C．Superconductors
D.
D．Superconductors

【参考答案】

A
本题考查考生把握细节的能力。考的是超导体和普通导体的区别。文章第二段的第二句话(Asuperconducto......

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下列( )不是宪法规定的内容。 A．国家性质 B．社会的经济制度 C．违宪责任 D．公民的基本权利和义务

A.国家性质
B.社会的经济制度

C.违宪责任

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More Rural Research is Needed1．Agricultural research funding is vital if the world is to feed itself better than it does now．Dr．Tony Fischer, crop scientist, said demand was growing at 2．5% per year, but with modern technologies and the development of new ones, the world should be able to stay ahead.2．'The global decline in investment in international agricultural research must be reversed if significant.progress is to be made towards reducing malnutrition(营养不良)and poverty,' he said.3．Research is needed to solve food production, land degradation(贫瘠化)and environmental problem．Secure local food supplies led to economic growth which, in turn, slowed population growth．Dr．Fischer painted a picture of the world's ability to feed itself in the first 25 years of the new century, when the world's population is expected to rise from 5.8 to 8 billion．He said that things will probably hold or improve but there'll still be a lot of hungry people．The biggest concentration of poor and hungry people would be :in subSaharan Africa and southern Asia in 2020, similar to the current pattern．If there is any change, a slight improvement will be seen in southern Asia, but not in subSaharan Africa．The major improvement will be in East Asia, South America and Southeastern Asia.4．The developing world was investing about 0．5%, or $8 billion a year, of its agricultural gross domestic product (GDP) on research, and the developed world was spending 2.5 % of its GDP．Dr．Fisher said more was needed from all countries.5．He said crop research could produce technologies, that spread across many countries, such as wheat, production research having spin-offs for Mexico, China or India.6．'Technologies still need to be refined for the local conditions but a lot of the strategic research can have global application, so that money can be used very efficiently,' Dr.Fischer said.7．Yields of rice, wheat and maize(玉米)have grown impressively in the past 30 years,especially in developing .countries．For example, maize production rose from 2 to 8 tonnes per hectare(公顷)between 1950 and 1995．But technologies driving this growth, such as high-yield varieties, fertilizers and irrigation, were becoming exhausted．'If you want to save the land for non-agricultural activities, for forests and wildlife, you're going to have to increase yield,' Dr．Fischer said. A．The Same or Improved Food Supply Situation in 2020B．Research Focus on Increased YieldC More Research Funding NeededD．Local Situations AnalyzedE．Increase in Investment on Agricultural ResearchF．Sustained Development of Modern Technologies 第 23 题 Paragraph 1____.