遇到巨大声响时,可迅速张嘴,使咽鼓管张开;或闭嘴同时双手堵耳,保持____ 两侧大气压力平衡,以免损伤鼓膜.
某小组在某温度下测定溶液的pH时发现,0.01mol/L的NaOH溶液中,c(H+)•c(OH﹣)=10﹣12(mol/L)2,则该小组在该温度下测得0.1mol/LNaOH溶液和0.1mol/LHCl溶液pH应为( )
Carol doesn't know what she should take for her trip. (改为同义句)
Carol doesn't know____ ____ ____for her trip.
4+47=□
语文综合实践活动。
围绕《专题·气象物候》,班级开展了系列语文综合实践活动。