Japan should play a “constructive” role at the upcoming G20 summit in the Chinese city of Hangzhou because cooperation is in the interests of all parties, China’s top diplomat told a visiting Japanese envoy.
V should play
O （a “constructive”） role
どこat （the upcoming） G20 summit （in the Chinese city of Hangzhou）
→どんなin the interests→どんなof all parties,
S （China’s top） diplomat
O (a visiting Japanese) envoy