My friend has a big police dog named Kim. Police dogs are often very smart. Every Sunday afternoon my friend takes Kim for a long walk in the park. Kim likes walking very much.
       One Sunday afternoon a man visited my friend. He talked to my friend for a long time. They talked and talked. Soon it was time for my friend to take Kim for his walk, but the man still stayed. Kim became very worried about his walk in the park. He walked around the living-room sometimes and at last sat down in front of the man and looked at him. But the man went on talking.
      After thirty minutes, Kim couldn’t stand(忍受) it. He went out of the room and came back a few minutes later.   He sat down in front of the man again but this time he held the man’s hat in his mouth.

风、霜、雨、雪等天气过程发生在大气垂直分层的（　　）

取5.0克氧化镁与氧化铜的混合物，加入稀盐酸（含0.2mol的HCl），恰好完全反应生成盐和水，原混合物中金属元素的质量是（   ）

①A与____组合，用于____，②B与____组合，用于____，

③B与____组合，用于____，④D与____组合，用于____．