thrash something out
phrasal verb with thrash verb uk/θræʃ/ us/θræʃ/
informal
彻底讨论（直到找到解决办法）;通过反复商讨解决
to discuss a problem in detail until you reach an agreement or find a solution
If we have an important decision to make, we sometimes spend a whole day thrashing it out in a meeting. 当我们要作重大决策时，有时会开一整天的会来商定。