We were worried that the event would be disorganized, but it all worked out in the end.

worked 是动词 work 的过去式，work 在这里表示"运作、起作用"。 out 是副词，表示"完全地、彻底地"或"最终结果"。 work out 是一个短语动词，意思是"顺利解决、最终有好的结果"。