大难题

例句：

1. 1.The company is facing a major challenge in its new product development.
   该公司正面临着在其新产品开发方面的重大挑战。
2. 2. The team has encountered a significant difficulty in completing the project on time.
   团队在按时完成项目上遇到了重大困难。
3. 3. This problem is considered to be a major obstacle in solving the issue.
   这个问题被认为是解决该问题的一个大障碍。