Unced
abbr. 聯合國環境與發展會議（United Nations Conference on Environment and Development）
??? 情景例句
After I finish my homeword, I usually watch TV for half an hour or so.
我做完作業后，通常看半個小時的電視。
I didn't do it on purpose.
我不是故意的。
You can enlarge your knowledge and learn some English at the same time.
你可以擴大你的知識面，同時又學習了英語。