U.N.

例句：

1. 1. The United Nations is a global organization that coordinates peacekeeping efforts.
   联合国是一个全球组织，负责协调维和努力。
2. 2. The United Nations is the seat of international diplomacy and negotiations.
   联合国是国际外交和谈判的场所。
3. 3. The United Nations has been working to promote human rights and democracy around the world.
   联合国一直在努力促进世界各地的人权和民主。