2.75+3.8+1.25=3.8+(____+____) 45.89-18.8-11.2=45.89-(____+____)
①滴加Mg(NO3)2溶液;②过滤;③滴加AgNO3溶液;④滴加Ba(NO3)2溶液.
—OK. I will go to Beijing next week.