knotty problem

例句：

1. 1.The problem with this project is that it's knotty and complex.
   这个项目的问题是它既棘手又复杂。
2. 2. The solution to the knotty problem was to reorganize the team.
   解决这个棘手问题的方法是将团队重新组织。
3. 3. The knotty issue of funding for the new project has been a major concern.
   新项目的资金来源棘手问题一直是主要关注点。