Complex sentence: The protests coincided with the events of the Prague Spring in neighboring Czechoslovakia--raising new hopes of democratic reforms among the intelligentsia--and culminated in the Warsaw Pact invasion of Czechoslovakia on 20 August 1968.
Split into simpler sentences: The protests coincided with the events of the Prague Spring in neighboring Czechoslovakia--raising new hopes of democratic reforms among the intelligentsia. The unrest culminated in the Warsaw Pact invasion of Czechoslovakia on 20 August 1968.