英语阅读理解~Here is an interesting way to write a “secret letter

英语阅读理解~
Here is an interesting way to write a “secret letter ”.You do it with the help of watermarks.If you collect stamps ,you know what a watermark is .On every stamp there is a mark .But you cannot see it .You can see it when you put the stamp in water .The mark is called “watermark“.The mark shows that you have a real stamp .People make watermarks on stamps by applying pressure(使用压力).In this way ,the watermark can be shown clearly in water because of the reflection (反射) of the light .It is easy to take watermarks and use them to write a “secret letter “.You put a piece of paper in water ,then take it out quickly and put it on a piece of glass .put a dry piece of paper on the top of it.
　Now you may write on the dry piece .You must use a hard pencil to apply pressure .When you raise the dry piece ,you will find that you can see everything you have written on the wet piece .When your wet paper becomes dry ,you will not see any -thing .But the words will be seen again if you put the piece of paper in water and take it out quickly .Now ,please try it and see how it works.
1 you can see the ____ when you put the stamp in the water
Aboy B ligtht Cletter D watermark
2 if a stamp is not a real one,we cannot see the watermark___
A when we put it on a piece of glass B when we put it in water
C when we put a piece of paper on it Dwhen we apply pressure on it
3 We can try to write a "secret letter "because______
Ait is easy to make watermarks B it is easy to get some piecces of paper
Cwe can use a hard pencil to do it Dpeople cannot see anything on wet paper
4 we must put a "secret letter " in water to see the words because the watermarks___
A reflect more light than the words on dry paper B are easy to see through in clear water C were made carefully in clera water D reflect light in a different way than they are wet
5 According to passage,how many things at least shall we use to write a"secret letter
A 3 B 4 C 6 D 7

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