工件的某一个自由度被两个定位元件重复限制，这种定位属于( )
A．过定位 B．欠定位C．完全定位 D．不完全定位
参考答案：A
看图，选词填空。
1. Look at my hair. It's _____________ and black. [ ]
A. short
B. long
C. young
2. This is my grandfather. He has _____________ hair. [ ]
A. black
B. green
C. white
3. This is my friend. She has _____________ and _____________ hair. [ ]
A. long; curly
B. long; straight
C. short; curly
下列选项中（）属于中和滤池。
A.普通中和滤池
B.降流式中和滤池
C.过滤中和滚筒
D.升流式膨胀中和滤池
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