throughout 是一个单词,意思是
始终,历来,在整个...里
throughout its history 在其历史里
把 throughout 写为 through out 是错的.
through 和 out 两个介词可以在同一句里用,但和 throughout 意思不同,比如：
The bird flew into the room through the open window and then out the front door.