union intersection principle

例句：

1. 1. The union of the two countries has brought about significant progress in their economic development.
   这两个国家的联合带来了他们在经济发展上的显著进步。
2. 2. The union of different cultures is what makes our world so rich and diverse.
   不同文化的结合是我们世界如此丰富和多样的原因。
3. 3. The union of two companies has led to the creation of a new product line.
   两家公司的合并导致了新产品线的诞生。