What's been achieved at the G20 Summit in Brazil?

①G20 leaders have reaffirmed their strong commitment to multilateralism and pledged to reform the global governance system at their summit in Brazil. What are the details? (00:58) ②Russian President Vladimir Putin has approved an updated nuclear doctrine that states Russia reserves the right to use nuclear weapons in the event of foreign aggression. What's the background? (25:32) ③ China's top economic planners have said that the country's economy is expected to maintain its recovery momentum in November and December, thanks to the effectiveness of its policy toolkit.(34:32) ④ This year's World Internet Conference Wuzhen Summit is in eastern China. What can be expected? (44:16)