搜题请搜索小程序“爱下问搜题”
问题 单项选择题

人耳对声波最敏感的频率范围是（）。

A.20～20000Hz

B.500～2000Hz

C.1000～3000Hz

D.125～8000Hz

E.8000～18000Hz

答案

参考答案：C

完形填空
完形填空
       Today is Saturday, Ann    1   to school. Her parents Mr King and Mrs King    2   to work. They want
to go to the Haishan Park. The park is near their house, so they   3    to the park. It's 9 o'clock now. There are    4   people in the park. Some people chat(聊天).Some people    5   .Some people sing. There are a
lot of good places to   6    fun in the park. Ann plays on the merry-go-round(旋转木马)    7    other boys
and girls. Mr King     8   in the sports club. Mrs King dances in the music club. They   9    it's very   10    .
( )1. A. don't go      
( )2. A. don't go      
( )3. A. takes a walk    
( )4. A. no              
( )5. A. play the guitar
( )6. A. having          
( )7. A. having          
( )8. A. plays tennis    
( )9. A. think          
( )10. A. relax          		B. doesn't go    
B. doesn't        
B. take a walk    
B. many            
B. play guitar    
B. have            
B .and            
B. play the tennis
B. thinks          
B. relaxing        		C. not go          
C. not go          
C. takes the walk  
C. a lots of        
C. plays the guitar
C. has              
C. with            
C. plays the tennis
C. thinking        
C. relaxed          		D. goes                
D. go                  
D. take the walk        
D. lot of              
D. plays guitar        
D. enjoy                
D. or                  
D. play tennis          
D. look                
D. boring              
查看答案
单项选择题

疲劳裂纹在第一阶段的扩展过程中是（）。

A．剪断

B．正断

C．扭断

D．弯断
查看答案