Complex sentence: On March 21 1960 the Sharpeville massacre occurred when the South African police opened fire on black civilians protesting the abhorred Pass Law, which restricted them to certain areas and forced them to carry passes at all times.
Split into simpler sentences: On March 21 1960 the Sharpeville massacre occurred when the South African police opened fire on black civilians protesting the abhorred "pass" laws. The pass laws restricted them to certain areas and forced them to carry passes at all times.