BEIJING (AP) — A top Chinese official said Thursday that “all-round efforts” are needed to ensure Tibetans speak standard spoken and written Chinese and share the “cultural symbols and images of the Chinese nation.” Wang Yang made the remarks before a handpicked audience in front of the Potala Palace in Lhasa, the home of Tibet’s traditional Buddhist leaders, at a ceremony marking the 70th anniversary of the Chinese invasion of the vast Himalayan region. China’s ruling Communist Party says it “peacefully liberated” Tibetan peasants from an oppressive theocracy and restored…