All the housewives who went to the new supermarket had one great ambition: to be the lucky customer who did not have to pay for her shopping. For this was what the notice just inside the entrance promised. It said, "Remember, once a week, one of our customers gets free goods. This May Be Your Lucky Day! "
For several weeks Mrs. Edwards hoped, like many of her friends, to be the lucky customer. Unlike her friends, she never gave up shopping. The cupboards in kitchen were full of things which she did not need. Her husband tried to advise her against buying things but failed. She dreamed of the day when the manager of the supermarket would approach her and say, "Madam, this is Your Lucky Day. Everything in your basket is free. "
One Friday morning, after she had finished her shopping and had taken it to her car, she found that she had forgotten to buy any tea. She dashed back to the supermarket, got the tea and went towards the cash-desk. As she did so, she saw the manager of the supermarket approach her. "Madam," he said, holding out his hand, "I want to congratulate you! You are our lucky customer and everything you have in your basket is free!"
Mrs. Edwards's husband tried to ____.（ ）
根据文章第二段 “Her husband tried to advise her against buying things but failed．”可知D选项正确。
把10gMgCl2和MgSO4的混合物溶于适量水中，滴加2mol／L的BaCl2溶液至沉淀完全，共消耗BaCl2溶液25mL。求混合物中MgCl2和MgSO4的质量各是多少克
固定在匀强磁场中的正方形导线框abcd，各边长为1．其中ab是一段电阻为R的均匀电阻丝，其余3边均为电阻可忽略的铜线。磁场的磁感应强度为B，方向垂直纸面向里。现有一与ab段的材料、粗细、长度都相同的电阻丝PQ架在导体框上，如图所示。PQ以恒定速度方向如何
一小物块以速度v0=10m／s沿光滑地面滑行，然后沿光滑曲面上升到顶部水平的高台上，并由高台上飞出，如图所示。问当高台的高度h多大时，小物块飞行的水平距离最大这个距离是多少(g=10m／s2)
某晶体盐的水溶液呈浅绿色，在此溶液中通入氯气，溶液变为棕黄色，把所得棕黄色溶液分成两份：一份加入KSCN溶液，溶液变深红色；另一份加入BaCl2溶液，产生不溶于稀HNO3的白色沉淀，则该晶体盐的化学式是_______。
欲除去乙烷中的乙烯，可将混合气体通过盛有_______的洗气瓶；欲除去乙炔中的硫化氢，可将混合气体通过盛有_______的洗气瓶。
浓硝酸常盛装在棕色瓶中，且贮放在冷暗处，原因是_______，
碳酸氢钠溶液和烧碱溶液反应的离子方程式为_______。
常温下，氨水中存在的离子有_______。
在酸或碱存在的条件下，甲酸甲酯跟水发生水解反应的化学方程式为_______。
有下列几种气体：H2、O2、HCl、NO、NH3、CH4，其中通常情况下能用来和水做“喷泉”实验的是_______。
