A video obtained by the Associated Press on Sunday has shown the aftermath of a six vehicle crash scene in New Jersey, US, that killed one and critically injured US actor and comedian Tracy Morgan.
Video supplied to AP by Will Vaultz Photography.
US officials continue the investigation of the crash that also left two others seriously injured.
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Mr Kim has made two recent visits to China.
The study looked at the development of 422 children over the course of eight years.
The president said they will come into force if China refuses to change its practices.