句中的that 和 threaten 分别是什么成分?这是一句什么从句?

问题描述:

句中的that 和 threaten 分别是什么成分?这是一句什么从句?
Marta had worked hard for a long time to win the scholarshi pjacket,but at the last moment something happened that threatened to rob her of the prize.

定语从句
that指代something,同时在定语从句中作主语,谓语为threatened