1 . But how do our phones know where in the world we are and in which direction we are going? It is all thanks to the satellites in space that help our phones ________ our position. ________ where you are around the world, your phone may be receiving data from different systems.（根据句意填空）

2 . They let the palace ________ (沦为一片废墟). (根据汉语提示完成句子)