So I had only known people of color. I only knew black people or Nigros as we called ourselves then or we are called.

所以，我所认识的人,就只有黑人而已,那时我们自称“黑鬼“,大家也都这么叫我们。

普林斯顿公开课 - 人性课程节选

It dropped dramatically in the period from 1954-- this is these filled black bars refer to this axis, polio cases per 100,000 population dropped down to only three or four cases by 1956.

患病率在一九五四年后的,一段时间里急剧下降,该坐标轴上的这些黑色柱形图表明,到一九五六年,小儿麻痹症的发病率,已经降低至每十万人中仅三到四人发病

耶鲁公开课 - 生物医学工程探索课程节选