it's this paper mend with a plastic cover and there's all these black magnetic particles here.

它是用这种纸以及一种塑料覆在上面,这里还有一些黑色磁性粒子。

哈佛公开课 - 计算机科学课程节选

And you get that reinforced on the very next page if you just skip over about a page from there: "A black pickup truck turned off a side road in front of him.

当你看到下一页时,这种感觉会加强,直接往后跳过一页：,“一辆小型黑色货车,在他面前拐进一条小路。

耶鲁公开课 - 1945年后的美国小说课程节选

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