题目

为提纯下列物质（括号内的物质是杂质），所选用的除杂试剂和分离方法都正确的是                                    被提纯的物质除杂试剂分离方法 A溴化钠溶液（NaI）氯水、CCl4萃取、分液 BCO（CO2）饱和NaHCO3溶液洗气 CFeSO4（Fe2(SO4)3）足量铁屑过滤 DCO2（SO2）NaOH洗气 答案：C阅读表达阅读短文，按要求完成短文后的各项 任务Have you ever thought about one question  ： why do we need to learn math?been asking it for years. For US students,  they may get the answer from a new exhibition called " MathAlive'" ( 1) The  organizers(组织者)have designed 47 activities to show kids  how they use math in everyday life.For example, at one exhi?bition station,  visitors can test that a person's arm span (臂 距)equals  their height.At another station, visitors can control the robot wilh the help of  math skills.The exhibition will visit 15 US and  international cities in the next five years.Organizers say they want more kicls  to learn why math is importanl in <lailv life. Think of simplr things,like  clocks.They tell time, but only if you know how to read them.That means using  math. How much longer until school ends? How long did you sleep last night?  Thai's all math ， loo.(2) When you go_,you also do lots  of_•How much change (零钱)would you get if you paid for a 25.99-yuan sweater with two twenlicsV How would you  cal?culate a 30% discount(折扣)? Even when you're not  doing math , it's all around you.The computer you use to surf the In?ternet is a  machine to do binary ( 二进制的)math very fast.So enjoy math, not for exams, but for the  vvondcrlul world it helps to build.1. 将（1)句译成中文。2. 在（2)句的空白处分别填入一个适当的词使句意完整、 上下文通顺。3. 回答问题•• Why will  the organizers hold the exhibition in 15 LS and international cities?4. 在文巾找出与Math skills  can help visitors control the m-bol.意思相近的句子。5. 在文中找出最能表达该短文主题的句子。