It’s often hard to find Chinese language interpreting practice material. The UN recently helped us trainee interpreters out by publishing an mp3 of a meeting in which Ambassador Li Baodong speaks at the Security Council. I’ve put a link to the mp3, at around 3 hours and 8 minutes.
The mp3 can be found here. It is on the UN News & Media Audio Library, which requires you to sign up for an account before you can download it. Don’t worry, it only takes a minute.
The transcript can be found here with the title 常驻联合国代表李保东大使在安理会表决英国等提交的叙利亚问题决议草案后的解释性发言.