题目

― Why was he late again? ― He arrived at the station late. _______ , he missed the early train. A. However     B. Because   C. Therefore    D. Though  答案：C  点拨：Therefore,连词“因此”， 故选C。下列实验能降低水的硬度的是（　　）A．吸附B．过滤C．沉淀D．蒸馏