hinge on/upon something
phrasal verb with hinge verb uk/hɪndʒ/ us/hɪndʒ/
依靠，取决于
If one thing hinges on another, the first thing depends on the second thing or is very influenced by it.
The prosecution's case hinged on the evidence of a witness who died before the trial. 控方的案子取决于一位证人的证词，而该证人已在审判前死去。
（故事或情况）围绕着…展开
If a story or situation hinges on an idea or subject, it develops from that idea or that is the most important subject in it.
The film's plot hinges on a case of mistaken identity. 该电影的情节围绕着一宗身份误认案展开。