Detailed Instructions: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
Problem:Chatham House , also known as the Royal Institute of International Affairs , is a London think tank .
Solution:
The Royal Institute of International Affairs , commonly known as Chatham House , is a not-for-profit and non-governmental organisation based in London whose mission is to analyse and promote the understanding of major international issues and current affairs .