题目

If you can look through the text before class，you will find it easy to __________ what the teacher teaches. A．take up                         B．take on C．take in                         D．take off 答案：C5．下列溶液中微粒浓度关系一定正确的是（　　）A．将水加热到100℃，pH=6：c（H+）＞c（OH-）B．室温下，pH=7的醋酸和醋酸钠的混合溶液中：c（CH3COO-）＞c（Na+）C．0.1mol•L-1 的硫酸铵溶液中：c（NH4+）＞c（SO42-）＞c（H+）D．同浓度的三种溶液：①CH3COONH4②NH4Cl③NH3•H2O中，c（NH4+）由大到小的顺序是②③①