Tom and Jenny are in the same school. And _________ like sports very much.          

①用pH试纸测试，测得pH为2。

②取一定量废水溶液，加入Ba（NO₃）₂溶液，无现象。

③另取一定量废水溶液，加入AgNO₃溶液后，过滤，得到白色沉淀A和滤液。

④向滤液中加入NaOH溶液，得到红褐色沉淀B。由此可知：该废水溶液呈____性；所得的红褐色沉淀B为____；废水溶液中肯定含有的盐是____。

    This is Joy's bedroom.it's a small room . He has some pictures.They are on the wall. He also has a desk and a chair in his bedroom.The desk is near the window. His bag and pencil box are on the desk. There are some pencils,a pen,a ruler in the pencil box. He has a baseball and a basketball. They are under the bed.Joy likes playing basketball and baseball. He also has two volleyb alls,but he doesn’t like playing volleyball.
根据短文内容，从A、B、C、D四个选项中选出能填入空白处的最佳选项。