问题 填空题
抛物线y=-
1
2
x2+1
的开口______,对称轴是______轴,顶点坐标是______.
答案

∵a=-

1
2
<0,

∴开口向下,对称轴x=-

b
2a
=0,是y轴,

-

b
2a
=0,
4ac-b2
4a
=1,

∴顶点坐标是(0,1).

完形填空
完形填空。

       Someday little cars may take the place of today's cars. If everyone   1  
such a little car in the future, and less pollution in the air, there will be more
parking space in cities,and the streets will be   2   crowded.The space now
for one car of' the usual size can hold    3one such little car.
      The little cars will   4   much less to own and to drive. Driving will
be    5    too, because these little cars can go only 50 kilometres an hour.
The cars of the future will be fine for going   6 the city, but they will not
be useful for going far away.The little car needs  only  two  batteries (电池)
 —one  battery for the motor, and    7    for the horn and the lights.If we
still   8    the big cars along with the small ones,we will need to   9  two
kinds of roads. Some roads will be used    10   the big fast cars, and others
will be  needed for the  small , slower ones.

( )1. A. drives  
( )2. A. more    
(     )3. A. at most 
(     )4. A. pay    
(     )5. A. faster  
(     )6. A. over    
(     )7. A. another
( )8. A. think  
(     )9. A. build  
(     )10.A.to      

B. sits
B. less 
B. no more  
B. spend    
B. harder  、
B. around  
B. one   
B. use     
B. put     
B. as      

 C. makes   
 C. much 
 C. less than
 C. cost    
 C. safer   
 C. from   
 C. the other 
 C. park    
 C. found   
 C.for      

D. sells 
D. fewer     
D. more than     
D. have        
D. more dangerous  
D. past           
D. others     
D. drove    
D. open        
D.in              

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