大问题

• great problem
• large problem

例句

1. 安全处置核废料是个大问题。
   The safe disposal of nuclear waste is a major problem.
2. 在一些发展中国家，文盲是个大问题。
   Illiteracy is a major problem in some developing countries.
3. 他们面临一个大问题。
   A great problem confronted them.