题目

The newly-published book, which ______ basic English grammar, is _____ only for beginners. A. regards as, meant  B. crowds in, intended  C. builds up, planned   D. refers to, intended 答案：B现有几种弱电解质的电离度（25℃，0.1mol?L-1）如下表：弱电解质α/%弱电解质α/%CH3COOH1.3NH3?H2O1.3HF7.8HCN0.0079根据上表数据，下列判断正确的是（　　）A．①CH3COOH②HF③HCN，三种一元酸的酸性由强到弱的顺序是③＞②＞①B．相同物质的量浓度的①CH3COONa ②NaF③NaCN的pH大小顺序是①＞②＞③C．向NaF溶液中加入盐酸，[Na+]不变，[H+]增大，[OH-]和[F-]减小D．NaF溶液中各种离子的浓度由大到小的顺序是[Na+]＞[F-]＞[OH-]＞[H+]