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问题 计算题

如图所示，用电压表分别测量L1两端的电压U1，L2两端的电压U2以及L1 , L2串联的总电压U，请根据表盘读数回答下列问题：

（1）L1两端的电压U1是多大？（2）L2两端的电压U2是多大？（3）L1 , L2串联的总电压U是多大？（4）电源电压是多大？

答案

(1)1.7V   （2）1.3V   （3）3V     （4）3V

题目分析：这是一个串联电路，灯L1和L2是串联，电压表U1测的是L1两端的电压，电压表U测的是电源电压，U的示数应该大于U1两端电压，而现在指针偏转小，所以U使用的是大量程， U­1使用的是小量程，故电源电压是3V ，L1两端的电压是1.7V，而串联电路的总电压等于各用电器两端电压之和，L2两端电压是3V-1.7=1.3V，而电源电压等于L1和L2两端电压之和，L1 , L2串联的总电压U是3V，电源电压是3V。

单项选择题

脊髓损伤后感觉功能不完全损伤的指征是什么

A．足部触觉存在
B．小腿触觉存在
C．大腿触觉存在
D．膝部触觉存在
E．肛门感觉存在
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填空题


In the following passage, there are 20 blanks representing the words that are missing from the context. You are to put back in each of the blanks the missing word． The time for this section is 20 minutes.
Where do you really come from And how did you get (1) where you live today DNA studies suggest that all humans today (2) from a group of African ancestors who—about 60,000 years ago— (3) a remarkable journey.
The Genographic Project is seeking to chart new (4) about the migratory history of the human species by (5) sophisticated laboratory and computer analysis of DNA contributed by hundreds of (6) of people from around the world． In this unprecedented and real-time (7) effort, the Genographic Project is closing the gaps of what science (8) today about mankind’s ancient migration stories.
The Genographic Project is a five-year (9) partnership led by National Geographic Explorer-in-Residence Dr. Spencer Wells. Dr. (10) and a team of renowned international scientists and IBM researchers, are (11) cutting-edge genetic and computational technologies to analyze historical patterns in DNA (12) participants around the world to better understand our human genetic roots. (13) three components of the project are: to gather field research data (14) collaboration with indigenous and traditional peoples around the world; to invite (15) general public to join the project by purchasing a Genographic Project Public Participation Kit; (16) to use proceeds from Genographic Public Participation Kit sales to further (17) research and the Genographic Legacy Fund which in (18) supports indigenous conservation and revitalization projects. The Project is anonymous, non-medical, (19) , non-profit and non-commercial and all results will be placed in the (20) domain following scientific peer publication.

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