As the last trace of color disappeared from her cheek, she gave her last breath.

VOA: special.2009.09.26

I don't know how many know that there are trace, trace amounts, of cyanide in almonds.

我不知道有多少人知道在杏仁中有非常，非常微量的氰化物。

麻省理工公开课 - 化学原理课程节选

Now the trace you notice on the left side has very few and very sharp deflections.

现在大家注意到左侧的变位,很少但是很剧烈。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

Trace quantities of vitamins occupy the same essential phenomenological niche in our food that trace amounts of rare earths occupy in our technologies.

FORBES: Tech's Mineral Infrastructure - Time to Emulate China's Rare Earth Policies

He is thought to have headed home to the Comoros islands in the Indian Ocean immediately after the attacks, but as FBI agents tried to trace him there, he boarded a plane to the Gulf and disappeared without trace.

BBC: Profile: Fazul Abdullah Mohammed

Mr Vine said the agency had failed to routinely or consistently make security checks to try to trace some of the unresolved cases that had been subsequently placed in the "controlled archive", a list of people UKBA officials believed they could not trace.

BBC: UKBA attacked over 'inaccurate' data given to MPs