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问题 选择题

如图所示，在点电荷Q产生的电场中，虚线表示等势面，实线表示α粒子（带正电）穿过电场时的轨迹，A、B为轨迹与两等势面的交点，则下列说法正确的是（　　）

A．Q可能是正电荷，也可能是负电荷

B．电势φA＞φB，粒子动能EkA＞EkB

C．电势φA＜φB，粒子电势能EPA＞EPB

D．场强EA＜EB，粒子动能EkA＞EkB

答案

A、由图，α粒子的轨迹向左弯曲可知，受到了斥力，而α粒子带正电，说明Q一定是正电荷．故A错误．

    B、C、Q带正电，电场线从Q出发到无穷远终止，则电势φA＜φB，由B到A的过程，电场力做正功，电势能减小，动能增加，即粒子动能EkA＞EkB，电势能EPA＞EPB．故BC错误．

    D、由公式E=k

Q
r2
得到，场强EA＜EB，又粒子动能EkA＞EkB．故D正确．

故选D

完形填空
完形填空。
     There is a park near my home. But I don't go there very often. One afternoon I went into   1    and
found it was really small. In the park, there were  two different ways. One  was wide and clean. There
were   2   flowers on   3   sides.   4 was narrow (狭窄的) and dirty. Wild grass grew everywhere. But
finally I decided to follow the dirty way.
      Ah! There was a small     5    there. It was the most beautiful garden I  had  ever seen. There were
trees,   6   and chairs. I thought  it was    7    part in the park.
      Many people    8     me that there is    9    to see in the park. Now I tell them   10    they follow the
right way, they can feel the difference. When I'm telling them,   11    just smile at me without answering.
I know they don't    12    me. My trip    13    the park that day made  me  understand  something about
    14   . Don't be   15   to choose a different way. Be brave (勇敢). You may get a big surprise!
( )1. A. the school
( )2. A. lots of  
( )3. A. every    
( )4. A. Another  
( )5. A. chair    
( )6. A.bikes      
( )7. A. the best  
( )8. A. tell      
( )9. A. something
( )10.A. if        
( )11.A. we        
( )12.A. know      
( )13.A. to        
( )14.A. study    
( )15.A. happy     		B. the park  
B. a lot      
B. each    
B. Other    
B. lake      
B. flowers  
B. better    
B. told      
B. anything  
B. when    
B. they      
B. believe    
B. of        
B. school    
B. lucky     		C. the zoo    
C. much      
C. all        
C. The other  
C. river      
C. buses      
C. good      
C. tells      
C. nothing    
C. after      
C. I          
C. understand
C. on        
C. family    
C. afraid     		D. the house        
D. any              
D. both              
D. Others            
D. garden            
D.cars              
D. nice              
D. telling          
D. everything        
D. before            
D. you              
D. agree            
D. in                
D. life              
D. worried          
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单项选择题 A1型题

神经与所支配肌肉的关系中，下列错误的是（）

A.桡神经深支--桡侧腕短伸肌

B.桡神经深支--尺侧腕伸肌

C.正中神经--拇对掌肌

D.正中神经--指深屈肌

E.尺神经--拇内收肌
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