题目

Everything comes with _____ price; there is no such _____ thing as a free lunch in the world. A a; a B the; / C the; a D a; / 答案：D教材中有一只小猫“捉迷藏”的趣味实验．用玻璃棒蘸取酚酞试液在滤纸上画一只小猫，如图所示，把滤纸放在浓氨水瓶口上方，滤纸上很快出现一只________色小猫，再把此滤纸放在浓盐酸瓶口上方，小猫________．该实验说明浓氨水和浓盐酸都易________，同时还说明浓氨水显________性，pH________7(填“大于”、“小于”或“等于”下同)，浓盐酸显________性．pH________7．