疆

例句：

1. 1. The border between China and India is very important.
   中国和印度之间的边界非常重要。
2. 2. The explorers crossed the border to reach the other side.
   探险家们越过了边境到达了另一边。
3. 3. The border region is rich in natural resources.
   边境地区资源丰富。