题目

 ---- Tony, you look puzzled. Have you understood me ?    ---- I’m sorry. I _____ another problem just now.      A. thought of                  B. am thinking of      C. had thought of               D. was thinking of 答案：D（2011?嘉兴）如图是氢氧化钠溶液与稀盐酸恰好完全反应的微观示意图，由此得出的结论错误的是（ ）A．反应结束时溶液的pH=7B．反应前后元素的种类没有变化C．反应后溶液中存在的粒子只有Na+和Cl-D．该反应的实质是H+和OH-结合生成水