She called on Eritrea to clarify the whereabouts of 11 MPs who disappeared without a trace in September,2001.

VOA: standard.2009.04.09

And as you'll see by your handout, I've attempted tend to trace it.

你们可以看看课堂材料，我尝试着去找，了找它的起源，我能找到。

麻省理工公开课 - 计算机科学及编程导论课程节选

You don't have to worry, we're definitely talking about trace, trace amounts.

但你不必担心，我们所说的绝对是非常，非常微量的。

麻省理工公开课 - 化学原理课程节选

Over the past few decades,however, scientists have determined that even trace amounts of lead in children's bodies leads to long-term neurological and behavioral problems.

VOA: standard.2009.12.19

We are also put in mind of how the war is, in fact, anything but a revel, though it, too, may have been provoked by a cause as insignificant and hard to trace as "some wizard vermin."

我们同样也思考事实上战争，只是一场狂欢，尽管它有可能,是由一个毫不重要难以追踪的“一些害虫“引起的“

耶鲁公开课 - 现代诗歌课程节选

At the same hearing, he says in one of the best studies used molecular fingerprinting to follow an outbreak of drug-resistant bacteria: "You actually can trace the specific bacteria around and they find that the resistant strains in humans match the resistant strains in the animals."

VOA: standard.2010.07.21

But then you can trace it to some external forces, which are carrying your iPod.

过一会儿你就能发现一些外力的作用,也就是有人把你的 iPod 拿走了

耶鲁公开课 - 基础物理课程节选