The stream of positive particles that meets the surge of electrons from the cloud often arises from a tall pointed structure such as a metal flagpole or a tower.
来自云层的电子流与正粒子流相遇，而这些正粒子流通常来自于高而尖的结构，如金属旗杆或塔。
3
If the data changes or if what you want to know changes-or if you want to combine the data with information from another stream or warehouse-you have to change the whole structure of the warehouse.