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问题 选择题

下列运算正确的是[ ]

A．a6÷a2=a3

B．（ab）4=ab4

C．（﹣a）6÷（﹣a）3=﹣a3

D．（﹣a3）2=﹣a6

答案

答案：C

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                                                  The earth needs a helping hand
       The earth is our home and it is in danger of being polluted. The earth is getting warmer because of the 
  1   of people. We   2   and bum trees and send gases into the air with our cars and factories. Can we do
anything about it? Sure. We may   3   be leaders or scientists but we can play our part in   4   the planet.
Here are two ideas.
       Bike, do ride to school
       Do you go to school by bus or by hike? If you bike, you are doing   5   for the earth.
       Buses, cars, trains and planes produce a lot of carbon dioxide (二氧化碳). If you live near to your
school,  6   bike there on warm spring mornings?  7  , you can simply walk to school to save energy.
       Wash in the green way
       Do you often help your mom wash clothes? Then wash them   8   an energy-saving way.
A recent study by Cambridge University found   9   60% of the energy used on a piece of clothing is   10  
 in washing and drying it. Over its lifetime, a T-shirt can   11   up to 4 kilograms of carbon dioxide into the
air.
         12   you wash your own clothes, wash them in cold or warm water to save energy, but not hot water. Wash your clothes when they fill up the machine. Use the most energy-saving machine you can find. Some
new ones use as   13   as one-fourth of the energy of older machines. When they're clean,  14   your clothes in the natural way, by hanging them on a line   15   putting them in a dryer. In all, you can cut the carbon
dioxide used in washing by 90%.
( )1. A. lives        
( )2. A. let down    
( )3. A. either      
( )4. A. protecting  
( )5. A. something    
( )6. A. how about    
( )7. A. And          
( )8. A. with        
( )9. A. what        
( )10. A. taken      
( )11. A. send        
( )12. A. As soon as  
( )13. A. much        
( )14. A. wash        
( )15. A. rather than 		B. waste          
B. cut down      
B. neither        
B. building      
B. anything      
B. let's          
B. But            
B. by            
B. that          
B. cost          
B. set            
B. SO            
B. little        
B. make          
B. would rather   		C. activities
C. turn down  
C. not        
C. repairing  
C. everything
C. why don't  
C. Or        
C. for        
C. why        
C. spent      
C. take      
C. If        
C. more      
C. wet        
C. instead    		D. land                  
D. sit down              
D. none                  
D. destroying            
D. nothing              
D. why not              
D. However              
D. in                    
D. how                  
D. paid                  
D. make                  
D. Unless                
D. less                  
D. dry                  
D. because of            
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选择题

近年来，每到春天,一场场铺天盖地的黄沙自甘肃河西走廊腾空而起，从西北到东南，几乎席卷大半个中国。据此回答1～3题。

1．下列四幅图中能反映“沙漠和荒漠化”主题的漫画是

A
B
C
D
[ ]

A．AB．BC．CD．D2．下列土地荒漠化较严重的地区是[ ]A．黄土高原北部B．辽东丘陵

C．山东丘陵

D．长江中下游平原

3．下列对土地资源利用现状的说法，正确的是 [ ]

A．在荒凉的陡坡上开垦耕地

B．在宜林荒坡上植树造林

C．农村新建的居民的住宅区，尽可能移到地形平坦的平原地

D．为了提高草场利用率，尽量增加放牧牲畜的数量

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