crux of the matter

例句：

1. 1.The crux of the problem lies infinding a solution that works for everyone.
   问题的关键在于找到一个对所有人都有效的解决方案。
2. 2. The crux of the argument is whether we shouldsupport the new policy or not.
   争论的核心是我们是否应该支持新政策。
3. 3. The crux of the discussion was about how toimprove the efficiency of our production process.
   讨论的核心是关于如何提高我们生产过程的效率。