A:1g
B:2g
C:3g
D:4g
What's Lili 's hobby? She likes ____.
①加入A时生成白色沉淀;
②往①沉淀中加入B时沉淀溶解,并有气体逸出;
③往②生成的溶液中加入C时,又有白色沉淀生成.
根据上述现象,回答: