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问题 单项选择题 A型题

颈总动脉分叉处可有以下彩色多普勒血流显像的正常变异（）。

A.彩色血流呈明显的五彩镶嵌

B.分叉处靠近膨大部有一些颜色不一的翻转彩色血流

C.彩色血流明显变细或时有时无

D.血流的彩色信号完全翻转

E.血流完全中断

答案

参考答案：B

问答题

【听力原文】My topic today is how to address the problem of hunger and starvation, which still exists in many parts of the world. To end hunger starts with people’s own productivity. A dangerous and patronizing cliche we often hear is: give a man a fish and feed him for a day; teach a man to fish and you feed him for life. People living with chronic hunger have generations of wisdom about ’fishing’ — the problem is the barbed wire around the lake. The hunger project announced recently by the United Nations cut through the barbed wire, addressing the underlying social conditions that systematically deny hungry people the opportunity they need to end their own hunger. When we invest in a hunger project, we are investing in people’s productivity and giving people a chance to translate their hard work into improved well-being. We are ensuring that people get the opportunities which are rightfully theirs. Too often hungry people are isolated, marginalized and exploited. Mobilizing communities and building local organizations is critically important — both to sustain the work we do and to get more out of our precious resources and efforts. When people come together to work, a kind of social capital is created that can compensate for the lack of financial capital in rural areas. In Africa, a unique feature of the hunger project’s work is to organize villages to work cooperatively on community land to produce food for food banks. This fosters collective responsibility and action for a better future for all. Another example is in some Asian countries, such as India and Bangladesh, where hunger project volunteer animators have catalyzed the creation of over 1,100 local organizations throughout the country. With nearly 50% ran by women, these local groups create savings programs and invest in individual and collective income generating enterprises, including sowing, tailoring and weaving projects, bakeries and small businesses, fish and poultry farming, bee keeping and plant nurseries. The impact of these enterprises is enormous. As women have become economically empowered, the decision-making roles have increased. As family incomes have often tripled, parents are sending more children — both girls and boys — to school.
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小明在做“测量小灯泡电功率”的实验中，所用器材有额定电压为2.5V的小灯泡，以及符合实验要求的电源、滑动变阻器、电表、开关和导线．实验前电压表和电流表已调零，实验时用导线a、b、c、d、e、f、g按图示方式连接电路．

（1）闭合开关前应把滑动变阻器滑片P调到______（选填“A”或“B”）端．

（2）闭合开关，调节滑动变阻器，结果出现了下列现象，请分析其原因：

a．小灯泡不亮，电压表示数始终为3V，电流表示数始终为零，则可能是导线______出现断路；

b．小灯泡能发光，电流表有示数，电压表示数始终为零，则可能是导线______出现断路．

（3）排除故障后，调节滑动变阻器，测得的三组数据如下表．则小灯泡的额定功率为______W．

实验次数123
电压U/V2.52.82.0
电流I/A0.300.320.26
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