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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fly freely in the sky because every vehicle will have wings with it. They
will__ __ you to any place you want to visit. You can go to__ __during
your travel when you feel tired. All vehicles will be__ __because
they're driven by robots.
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fly freely in the sky because every vehicle will have wings with it. They
will__ __ you to any place you want to visit. You can go to__ __during
your travel when you feel tired. All vehicles will be__ __because
they're driven by robots.