Question

How did China’s relationship with the Soviet Union and the United States change during the Cold war?

Answer 1

Since China became a communist government, they became allies with  the Soviet Union.   China moved away from the US as they did not share the same values.    
Years later, Richard Nixon, made huge improvements in the relations with both China and the Soviet Union. He called his visit, to China "the week that changed the world".  

Reference: https://en.wikipedia.org/wiki/Richard_Nixon%27s_1972_visit_to_China