关于地球仪的叙述，正确的是（　　）

    December 25 is Christmas Day(圣诞节). Christmas is an important holiday in many countries. On Christmas Day, most families get together for a big dinner. They give presents to each other and visit friends. The Christmas tree is an important part of the Christmas holiday. Most families buy trees. The families decorate(装饰) the tree together. Parents usually tell their children that Father Christmas comes during the night and brings presents to good children. Of course, Father Christmas isn't real. The parents of the children are really "Father Christmas". They put the presents under the tree or into their children's stocking(长统袜) after the children go to sleep.

含有硝酸锌、硝酸铁、硝酸镁、硝酸铜、硝酸银五种溶质的溶液中加入一定量的铁粉，充分反应后过滤，滤纸上一定有____ ，可能有____ 　；滤液中一定有____ ，可能有____ ；如果滤纸上有铁，则滤纸上一定同时有____ ，滤液中一定没有　____ ．