The relationship between the world 's sole superpower United States and the emerging superpower status of the PRC is closely watched by international observers .
Hu Jintao and US president George W. Bush , with first ladies Liu Yongqing and Laura Bush , wave from the White House .
The relationship between the world 's sole superpower US   and the emerging superpower status of the PRC is closely watched by international observers .
Hu Jintao and US president George W. Bush , with first ladies Liu Yongqing and Laura Bush , wave from the White House .