问题 选择题
2002年诺贝尔物理学奖中的一项,是奖励美国科学家贾科尼和日本科学家小柴晶俊发现了宇宙X射线源.X射线是一种高频电磁波,若X射线在真空中的波长为λ,以h表示普朗克常量,c表示真空的光速,以E和m分别表示X射线每个光子的能量和质量,则(  )

A.E=,m=0

B.E=,m=

C.E=,m=0

D.E=,m=

答案

答案:D

完形填空


完形填空
         It's Sunday and it is a  1  day. People don't stay  2  home. They go to parks and beaches or
drive(开车) to the country(乡村).
         Now we  3  at the seaside(海边).There  4  lots of people on the beach.  Some   5  . Some
are  6  on the sand and bathing(沐浴)  7  the sun Over there a group of men and women  are
sitting under a beach umbrella(雨伞). They are    8    and laughing. Not far from them, a little boy  is
playing   9  water. The people are really 10   .
                                                                                             
( )1. A. sun          
( )2. A. in            
( )3. A. are          
( )4. A. are          
( )5. A. are  swimming
( )6. A. lie          
( )7. A. und er        
( )8. A. say ing      
( )9. A. with          
( )10.A. relax         
                       
B .sunning      
B. at            
B. come          
B. is            
B. swim          
B. in            
B. in            
B. speaking      
B. at            
B. relaxing      
                
C. suny        
C. on          
C. get        
C. have        
C. swims      
C. lying      
C. on          
C. talking    
C./          
C. relaxed     
              
D. sunny            
D. of                
D. go                
D. come              
D. is swimming      
D. lieing            
D. over              
D. telling          
D. to                
D. relaxs            
                  
单项选择题