下列物质中属于纯净物的是（ ） A．银 B．碘酒 C．不锈钢 D．矿泉水

           Everyone    1   air. Air is all around us. lt's around us when we go and play. Since we were bom,air has been around us on every side.  2  we sit down,it's aroundus. When we go to bed,air is     3   around us. So we can say we live in air.

          All living things   4   air. Living things can't live   5   air. We can go without food or water for more than a few days. But we can't live for more than a few    6   without air. When we are sleeping,we need less air.

         We live in air,_7  we can't see it. We can only feel it. We can feel it when  it  is  moving (移动 ) . Moving air is wind.    8_can you make air move?  Here is one   9   . Hold an open book in your hands in front of yourface. Close it   10   , and what can you feel?  It's air.

( )1. A. know    '  B. knows                   C. knowing          D. knew    

( )2. A. When       B. What                    C. Why               D. How      

( )3. A. also          B. too                       C. either              D. neither  

( )4. A. like          B. don't like               C. needs             D. need    

( )5. A. with         B. thout                      C. for                 D. of      

( )6. A. years       B. days                       C. minutes          D. months  

( )7. A. but          B. because                   C. so                 D. if      

( )8. A. Why        B. How                       C. What            D. Where    

( )9. A. way         B. road                        C. street           D. bench    

( )10.A. quick      B. terrible                     C. soon           D. quickly  

刃磨錾子时，必须戴好防护眼镜。( )

属于安全生产违法行为行政处罚的种类有（）。

A.责令停产停业整顿、责令停产停业、责令停止建设

B.拘留

C.关闭

D.吊销有关证照

榜样包括伟人的典范、______的示范和______。

关于生后肾原基的描述，错误的是（）。

A．来源于生肾索的尾端部分

B．在输尿管芽的诱导下分化

C．分化为肾单位

D．形成肾小管和集合小管