Text: Thirty years may seem like a long time to someone nursing a grievance since the pitched battles of the late '60s, but in the sweep of history--on the heels of 90 years of Jim Crow and 200 of race slavery--it's nothing.
Entailment: 30 years may seem like a long time to an individual, but it is nothing compared to the long history of race relations in the United States.
Contradiction: 30 years is an extraordinarily long time for a civil rights marcher, even in the grand scope of history.