2Fe（NO3）3+16NaOH+3Cl2═2M+6NaNO3+6NaCl+8H2O则M的化学式为（ ）
A：Na2Fe2O8
B：NaFeO4
C：Fe2NaO4
D：Na2FeO4
A．物质用途
B．元素之最
液氮：用于医疗手术
明矾：用于消毒杀菌
海水中含量最多的元素：钠元素
空气中含量最多的元素：氮元素
C．物质鉴别
D．环保知识
硬水和软水：加入肥皂水
氢气和二氧化碳：用燃着的小木条
减缓温室效应：植树造林节能减排
减少水体污染：禁止使用洗涤剂
—Of course. You ________ never be careful enough with that.
– I am reading the newspaper to look for(找) a job –_______.
— Chinese women's volleyball team won the gold medal in 2016 Rio Olympic Games.
—______ Chinese people were at that time!
