题目

下列关于氯水的叙述正确的是（ ）     A．新制氯水可使蓝色石蕊试纸先变红后褪色 B．光照氯水有气泡放出，该气体是Cl2     C．新制氯水中只含Cl2和H2O分子          D．氯水放置数天后酸性将变弱 答案：A Most people usually have less money at the end of the month than ____ at the beginning.     A. which is             B. which was           C. they have             D. it is