Answer:
1948-yugoslavia parted ways with the soviet union because of political differences.
1956-workers in poland won higher wages after an uprising.
1961-military forces began constructing the berlin wall
1968-The soviet union invaded czechoslovakia and reversed its economic reforms.
Step-by-step explanation:
Yugoslavia was actually expelled from the USSR due to the nationalism that its leader Tito had going and he didn´t like many of the policies that the USSR was applying so they were accused of treason and were expelled from the soviet union. In 1956 workers in poland riotted and protested to ask for better working conditions and wages, were the first protests against a communist regime, in august 2nd 1961 the army and military forces of german democratic republic built the berlin wall, and in 1968 the soviet union invaded czechoslovakia reversed its economic reforms.