①垂头丧气:____
②兴致勃勃:____
③盘问:____
Some girls are studying in the classroom and the ____ girls are singing on the playground. (other/else)
将0.4%的氢氧化钠溶液滴加到2mL0.4%的盐酸中,测得混合液的pH变化曲线如图.某学习小组对加入0~VmL氢氧化钠过程中,所得混合液pH增大原因进行了如下探究: