knot problem

例句：

1. 1. The knotty problem of finding a suitable candidate forthe job has been solved.
   找到合适的候选人解决这个棘手的问题已经解决了。
2. 2. The knotty issue of how to balance work andpersonal life is still unresolved.
   如何平衡工作和个人生活这个棘手的问题仍然没有解决。
3. 3. The knotty problem of fundingthe project has become increasingly difficult to overcome.
   项目资金的棘手问题变得越来越难以克服。