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　　Do you like to go camping(野营)？Do you know how to start a fire？If you don't know how to start a fire，you 　　1　　 your food，and can't sit by the side of a fire，and can't keep yourselves 　　2　　 ．

　　Long，long ago people 　　3　　 how to start fires．They probably started fires from lightning (闪电)．But they had to 　　4　　 the lightning fire burning，for there was 　　5　　 to start it 　　6　　 ．

　　Later people learned how to start fires．They 　　7　　 out hitting two pieces of stone(石头) together could make a spark(火光)．The spark could set 　　8　　 on fire(set…on fire使……燃烧)．They could start this kind of fire again if it went out(熄灭)．

　　Then people also learned to make a fire by rubbing(摩擦)two sticks together．They made a hole(洞)on a large stick and put the 　　9　　 stick into the hole．And then they turned the stick again and again， 　　10　　 a few minutes they started a fire．

　　About two hundred years 　　11　　 ，people began to 　　12　　 matches(火柴)．One early match looked 　　13　　 the match we use today．The match gave people a 　　14　　 way to start fires．Today people are 　　15　　 finding new ways to start fires．One of the new ways to start a fire is to use an electric fire starter(电子打火器)．Now you can 　　16　　 matches and electric fire starter at 　　17　　 ．Of course an electric fire starter is more expensive than 　　18　　 ， 　　19　　 it is useful．

　　After people learned to make fires，their lives became 　　20　　 ．

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