英语周报fjm版2020~2021年答案

8.解析:选BA. NaSO4晶体是钠离子和硫酸氫根离子构成,晶体中不含氤离子,故A错误;B.计算乙醇物质的量=:46=1mol,不同原子形成的共价键为极性46g/m共价键,结合乙醇分子结构得到极性共价键数目7NA,故B正确;C.1L0.1mol·L的Na2CO3溶液中存在物料守恒,n(Na)=n(C),溶液中H2CO2、HCO2和CO离子数目之和为0.1NA,故C错误;D.醋酸铵中醋酸根离子和铵根离子都发生水解相互促进,水电离程度增大,由水电离产生的H的数目大于10~NA,故D错误。

书面表达One possible version:NOTICEA sports meeting will be held in the playground of our school from next Thursday to FridayAs you know, the pressure of study is very heavy now, especially for those senior 3. So the purpose of the sports meeting is to letevery student get relaxed, as a result of which we students can live happily and heal thilyEveryone is welcome to take part in it. Those who perform excellently at the sports meeting will get prizes. But don' t take theresults so serously because taking part is more important than the result. Good luck to everyone!

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