“不可替代的作用”怎么翻译？

Part One 热词

1. 海淘：buy products from overseas websites   

2. 减免：money-off  

3. 社保基金：social security funds

4. 延迟退休：delay/postpone retirement  

5. 养老保险：pension insurance  

Part Two 汉译英

原文：70年来，作为最具代表性和权威性的政府间国际组织，联合国依靠和平与安全、发展、人权三大支柱，为促进人类进步事业发挥着不可替代的作用，并取得了巨大成就。

译文：In the past 70 years, as the most representative and authoritative intergovernmental organization in the world, the UN, with its three pillars of peace and security, development, and human rights, has played an irreplaceable role and accomplished a great deal in promoting human progress.

自学笔记：

1. intergovernmental [ˌɪntərˌgʌvərnˈmentl]  ADJ 政府间的

2. with its three pillars of peace and security, development, and human rights：with表示“借助于；依靠”

3. pillar [ˈpɪlɚ] N-COUNT （制度、协议等的）支柱，核心

4. irreplaceable [ˌɪrɪˈplesəbəl] ADJ （因贵重或独特）不能替代的

    play an irreplaceable role in (doing)具有不可替代的作用

5. accomplished a great deal与played an irreplaceable role为并列成分