[单项选择]Fire can help people in many ways. But it can also be very harmful(有害的). Fire can keep your house (41) ,give light and cook food. But fire can bum things, (42) . Big fire can bum trees, houses, animals or people. Nobody knows how people began to use fire. But there are (43) interesting old stories about how a man or woman started a fire. One is (44) a man. The man (45) a very long time ago. He went up the sun and (46) fire down. Today people know how to make a fire with matches (火柴). Children sometimes like to play with (47) . But matches can be very dangerous. One match can burn (48) , and than it could burn a house. A small fire can turn into a big fire very quickly. So you (49) be careful with matches. Be careful with fire, and it will (50) you. But if you aren’t careful with fire, it may hurt you.
