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问题 单项选择题

利用电子学的方法，在天线做方位扫描时对一个给定的距离上，多个相继取样的回波视频信号进行累加平均，称为（）。

A.视频积分

B.方位积分

C.距离积分

D.傅利叶变换

答案

参考答案：B

完形填空
完形填空。

     What should we do to keep healthy? One important rule is to exercise    1   . The Fang family try to exercise
every day. Mr Fang    2    exercise in the morning because he must get to work at exactly seven o'clock. But he
runs every evening. He walks a lot,    3   . He walks to school every day, and after school he    4    different
sports with his friends. Mr Fang goes to a yoga (瑜加功) class    5   .
     But it wasn't    6    this way. Last year Mr and Mrs Fang used to (过去常常)    7    everywhere in their car,
even to the drugstore (药店) two blocks (街区) away. They thought they had to use the car all the time. They
wouldn't walk. 
    The Fangs all    8    better now. They believe they shouldn't be lazy. We    9    exercise every day, but we
should try our   10   to exercise as often as possible.

( )1. A. often         
( )2. A. may not       
( )3. A. either        
( )4. A. watches       
( )5. A. in two weeks  
( )6. A. always        
( )7. A. riding        
( )8. A. had           
( )9. A. needn't       
( )10. A. best       

B. sometimes     
B. can not       
B. also          
B. plays         
B. for two weeks 
B. even          
B. drive         
B. make          
B. don't         
B. good          

C. late             
C. would not        
C. too              
C. loves            
C. after two weeks  
C. sometimes        
C. fly              
C. feel             
C. won't have       
C. well           

D. later        
D. should not   
D. again        
D. likes        
D. twice a week 
D. no           
D. walk         
D. feel like                           
D. mustn't      
D. better       
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填空题

如果∠1+∠2=90度，∠1+∠3=90度，那么∠2=∠3．理由是______．
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