We must maintain the hard-won achievements of the 1.4 billion Chinese people and uphold the overall strategic vision of the great rejuvenation of the Chinese nation, former Chinese ambassador to the United States Cui Tiankai said on Monday at a symposium on the international situation and China's diplomacy in 2021. China-U.S. relations are at a historic stage that will last for quite some time, Cui said, stressing that we need to be clear-headed and fully prepared to deal with the twists and turns of China-U.S. relations in the future.