United States and China are the world's largest and second largest economies respectively, although China has a larger GDP when measured by PPP. China is the second largest foreign creditor of the United States, after Japan. Washington efforts to encourage American banks to invest in Chinese railways was unsuccessful in the 1900s. President Franklin Roosevelt made support of China against Japan a high priority after 1938. The US was allied to the Republic of China during the Pacific War against Japan (1941-1945). Washington tried and failed to negotiate a compromise between the Nationalist government and Chinese Communist Party (CCP) in 1945-1947. After the victory of Mao Zedong's CCP in Mainland China during the Chinese Civil War, relations soured. China as a currency manipulator. The Trump administration labeled China a ''strategic competitor'' starting with the 2017 National Security Strategy. We're starting to get anxious, because that has never happened. Over that age, there would not be enough parent isotope atoms left to get accurate dating information using this isotopic dating method. Using such rationale, the sequence of geological events can be better understood.