问题 填空题

小明家中电能表的参数如图所示,他家同时使用的用电器总功率不能超过      W;五月初     抄表的示数如图所示,若五月份交电费42元,且电价为0.5元/度,则五月末抄表的示数为      kW·h,若1min内电能表的转盘转过10r,则这段时间内,小明家所使用的用电器的总功率为      W。

   

答案

2200   2797.5   500

题目分析:由电能表的参数可知,用电器总功率不能超过P=UI=220V×10A=2200W;五月消耗的电能为W=42元/(0.5元/度)=84kW·h,则五月末抄表的示数为2713.5 kW·h+84kW·h=2797.5kW·h。1min内小明家所使用的用电器消耗的电能为W=(10/1200)×3.6×106J=30000J,小明家所使用的用电器的总功率为P=W/t=30000J/60s=500W。

完形填空
完形填空
       There was a robbery near Harry's home one night. Harry was looking out of his window   1  . He saw a robber run out of a shop and he saw the robber    2   his mask (面具).  He saw his face.
       Harry told his father what he had seen. When the police came,Harry and his   3   went to talk to them. "I saw the robber, " Harry told the police., "I can    4   him. He was about fifty years old. He   5   a big red nose. His ears were big. He was quite tall and thin.  He had   6   wrong with his right leg. "
       "  7   do you know that?" one of the policemen asked Harry.
       "He lamed (跛行), " Harry said.
        "What was he wearing?" the other policeman asked.
       "He was wearing black trousers and a shirt, " Harry said.
        "Hismask was a lady's stocking. His shoes were white sports shoes. "
       "You are a very clever boy, " the policeman said. "  8   ! Now we can send out a description of the
robber.
       " The police did this and the next day they caught him. They put him in a line   9    some other men.  
They asked Harry to point him out.  Harry did this _10_ The police arrested (逮捕) the man. Then Harry went home with his father happily.
( )1. A. at that time    
( )2. A. put on          
( )3. A. policeman      
( )4. A. tell            
( )5. A. wore            
( )6. A. nothing        
( )7. A. How            
( )8. A. I'm afraid not  
( )9. A. on              
( )10. A. easily        
B. at this moment
B. put off        
B. mother        
B. describe      
B. had            
B. everything    
B. What          
B. Of course      
B. for            
B. badly          
C. at last      
C. take out    
C. father      
C. ask          
C. took        
C. anything    
C. Why          
C. Well done    
C. with        
C. sadly        
D. at the beginning      
D. take off              
D. brother              
D. greet                
D. put                  
D. something            
D. When                  
D. It doesn't matter    
D. after                
D. suddenly              
单项选择题