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问题 单项选择题

锯条有了锯路后，使工件上的锯缝宽度()锯条背部的厚度，从而防止了夹锯。

A、小于 

B、等于 

C、大于 

D、小于或等于

答案

参考答案：C

完形填空
完型填空。
     Mary has some friends.    1  Betty, Peter, Alice   2   Mike. Mary is the oldest   3  . Betty is thirteen
years   4  . She is younger than Mary and older than Peter. Alice is nine and Mike is seven.
     Betty and Peter are   5   runrung. But Peter runs faster. Mary and Betty like to _6  . Mary plays
better than Bettey. Alice sings   7   0f them. Mary and Betty study in a middle school. Alice and Mike
study in a primary school. They   8   work hard at school. But Betty works   9  . Her handwriting is
good,   10  .
( )1.A. They are      
( )2.A. but            
( )3.A. in the five    
( )4.A. older          
( )5.A. best          
( )6.A. play basketball
( )7.A. good          
( )8.A. six            
( )9.A. hard          
( )10.A. too           		B. It is            
B. or              
B. of five          
B. old              
B. better          
B. play a basketball
B. better          
B. all              
B. harder          
B. two              		C. There are          
C. so                
C. of the five        
C. oldest            
C. well              
C. play the basketball
C. best              
C. four              
C. veryhard          
C. at                 		D. We are          
D. and              
D. for the rive    
D. very old        
D. good            
D. play basketballs
D. well            
D. both            
D. hardest          
D. also            
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单项选择题

硬度是矿物区分的一个重要指标。下列矿物中能在其它三种上刻出痕迹的是（）

A.方解石

B.长石

C.石英

D.刚玉
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