摘要:22.-- ?--Boil the noodles.A.What should we do next B.What did you have for breakfastC.What do you think of the noodles D.What's the matter

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A Simple Scientific Experiment

Below is a description of a single scientific experiment. It shows us how iron reacts ( 反应) with air and with water.
Aim : To find out if iron rusts( 生锈) (a) in dry air ; (b) in water that has no air in it ( air- free water) ; (c) in ordinary water.
Materials : 3 clean iron nails ( 铁钉) ; test tubes ; test tube holder ; cotton wool ; oil ; Bunsen burner.
Iron in dry air
Method
(1)Put some iron nails at the bottom of a test tube.
(2)Push some cotton wool down the tube.
(3)Leave the tube for one week.
Result
After one week, the nails have not rusted.
Conclusion
Iron does not rust in dry air.
Iron in air-free water
Method
(1)Half-fill a test tube with water.
(2)Boil the water for three minutes. (This makes sure there is no air in the water.
(3)Put two or three clean nails in the water.
(4)Add some oil to the water. (This will keep air out of the water.)
(5) Leave the tube for one week.
Result
The nails do not rust in the tube with air-free water.
Conclusion
Iron does not rust in air- free water.
Iron in ordinary water
Method
(1)Half –fill a test tube with water and add two or three clean nails.
(2)Leave the tube for one week.
Result
The nails rust in the tube with ordinary water.
Conclusion
Iron rusts in ordinary water. (238 words)
【小题1】In the first part of the experiment the cotton wool is most probably used to ______________.
A.keep the air dryB.keep the tube wet
C.make the nails rustD.keep the tube clean
【小题2】What are necessary steps to make sure the water in the tube is air free?
①Leave half a tube of water in it              
②Boil the water for some time
③Put some clean iron nails in the tube           
④Add some oil to the water
A.①②B.①③C.②③D.②④
【小题3】We can conclude from the experiment that only ____________ makes iron rusty.
A.dry airB.cotton woolC.ordinary waterD.air-free water

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A Simple Scientific Experiment

Below is a description of a single scientific experiment. It shows us how iron reacts ( 反应) with air and with water.

Aim : To find out if iron rusts( 生锈) (a) in dry air ; (b) in water that has no air in it ( air- free water) ; (c) in ordinary water.

Materials : 3 clean iron nails ( 铁钉) ; test tubes ; test tube holder ; cotton wool ; oil ; Bunsen burner.

Iron in dry air

Method

(1) Put some iron nails at the bottom of a test tube.

(2) Push some cotton wool down the tube.

(3) Leave the tube for one week.

Result

After one week, the nails have not rusted.

Conclusion

Iron does not rust in dry air.

Iron in air-free water

Method

(1) Half-fill a test tube with water.

(2) Boil the water for three minutes. (This makes sure there is no air in the water.

(3) Put two or three clean nails in the water.

(4)Add some oil to the water. (This will keep air out of the water.)

(5) Leave the tube for one week.

Result

The nails do not rust in the tube with air-free water.

Conclusion

Iron does not rust in air- free water.

Iron in ordinary water

Method

(1) Half –fill a test tube with water and add two or three clean nails.

(2) Leave the tube for one week.

Result

The nails rust in the tube with ordinary water.

Conclusion

Iron rusts in ordinary water. (238 words)

1.In the first part of the experiment the cotton wool is most probably used to ______________.

   A. keep the air dry                            B. keep the tube wet

   C. make the nails rust                          D. keep the tube clean

2.What are necessary steps to make sure the water in the tube is air free?

①Leave half a tube of water in it              

②Boil the water for some time

③Put some clean iron nails in the tube           

④Add some oil to the water

  A. ①②                  B. ①③                 C. ②③                D. ②④

3.We can conclude from the experiment that only ____________ makes iron rusty.

A. dry air       B. cotton wool           C. ordinary water         D. air-free water

 

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完形填空。
       Newton (牛顿) was a great English scientist. He was one of the greatest     1     in history. One
morning he got up early and began     2     on a difficult problem. It was time to have breakfast, but he
was thinking     3    the problem. Her servant, Mary brought a pan of water and egg to his room. She
was going to boil (煮) the egg for him. But Newton wanted to do by     4    . He said to Mary, "Please
put the egg on the table. I'll boil     5    ." 
       Mary put the egg beside Newton's watch on the table and     6   , "Boil the egg for only four minutes
and it'll be     7    . "Then quickly she walked out of the room. Mary was afraid Newton would     8     to
boil the egg. She went to his room again half an hour later. What did she     9   ? Newton was standing by
the pan, having the    10    in his hand. He had put the watch in the pan and was boiling it .
(     )1. A. woman  
(     )2. A. work   
(     )3. A. ∕     
(     )4. A. itself 
(     )5. A. one    
(     )6. A. said   
(     )7. A. free   
(     )8. A. forget 
(     )9. A. look   
(     )10. A. pen         
B. women     
B. to work   
B. about     
B. herself   
B. ones      
B. told      
B. ready     
B. want      
B. looked    
B. egg             
C. man       
C. try       
C. for       
C. himself   
C. it        
C. spoke     
C. bad       
C. decide    
C. see             
C. book   
D. men        
D. to try     
D. over       
D. themselives
D. them       
D. talked     
D. well       
D. need                          
D. san        
D. watch      
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