写出下列物质的化学式：
（1）纯碱______；
（2）烧碱______；
（3）大理石的主要成分______；
（4）地壳中含量最多的金属元素______；
（5）目前使用量最大的金属______．
（1）纯碱是碳酸钠的俗称，其化学式为：Na2CO3．
（2）烧碱是氢氧化钠的俗称，其化学式为：NaOH．
（3）大理石的主要成分是碳酸钙，其化学式为：CaCO3．
（4）地壳中含量最多的金属元素是铝元素，其元素符号为：Al．
（5）目前使用量最大的金属是铁，其化学式为：Fe．
故答案为：（1）Na2CO3；（2）NaOH；（3）CaCO3；（4）Al；（5）Fe．
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| In England nobody under the age of eighteen is allowed to drink in a public bar. Mr Brown usually went to a bar near his house, but he 1 took his son, Tom, because he was too 2 . Then, 3 Tom’s 18th birthday, Mr Brown took him to his usual bar 4 the first time. They drank for half an hour, and then Mr Brown 5 , “Now, Tom, I will tell you a 6 . You must always be careful not to drink too much. And how do you know when you’ve had 7 ? Well, I’ll tell you. Can you see those two lights 8 the end of the bar? When they seem to have become 9 , you’ve had enough and 10 go home. ” "But Dad, ” said Tom, “I can see only one light there !” | ||||
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