Complex sentence: The Civil Rights Movement was gathering momentum, and in 1964 urban riots began within black neighborhoods in New York City and Los Angeles; by 1968 hundreds of cities had major riots that caused a severe conservative political backlash.
Split into simpler sentences: The Civil Rights Movement was gathering momentum, and in 1964 urban riots began within Black neighborhoods in New York City and Los Angeles. By 1968 hundreds of cities had major African-American riots that caused a severe conservative political backlash.