哄____大____       两____三____     随____所____

____哉____哉       能____善____

    Hello!My name is Bob. My classroom is not big but nice. There are 21 desks and 20 chairs. 墙上有一些画和一幅地图。Mrs Brown is our English teacher. She is from a big city.She is nice. Her husband Mr Brown is a teacher too, but he isn't in our school. Tom is my good friend. We like playing football on Saturday. Where is my football? It is under my desk.     

按如图所示装置进行实验（图中铁架台等仪器均已略去）．先在试管Ⅱ中加入试剂乙，然后在试管Ⅰ中加入试剂甲，立即塞紧橡皮塞，一段时间后，观察到试管Ⅱ中有白色沉淀生成．符合以上实验现象的一组试剂是（    ）