题目

How old is the woman now?A. 20 years old. B. 45 years old. C. 65 years old. 答案：【答案】B【解析】W: When I’m 65 I will get Social Security payments from the government.M: That means you have twenty years to go and then you can quit your job.此题为听力题，解析略。19．用高锰酸钾标准溶液滴定加入稀硫酸酸化后的过氧化氢溶液，能测定溶液中过氧化氢的含量，并探究过氧化氢的性质．滴定过程中反应的离子方程式如下，请将相关物质的化学计量数及化学式填写在方框里．