When melting snow-crystals or raindrops fall through very cold air, they freeze to form small particles of ice, called sleet.

VOA: special.2011.01.11

These very small particles are able to specifically recognize certain kinds of cells.

这些微小的小颗粒,可以识别特定种类的细胞

耶鲁公开课 - 生物医学工程探索课程节选

So, then we'll get to turn to a new kind of mechanics or quantum mechanics, which will in fact be able to describe what's happening on this very, very small size scale -- so on the atomic size scale on the order of nanometers or angstroms, very small particles.

然后我们要讲到一种,新的力学--量子力学,它可以解释,发生在很小尺度,大约是原子尺寸大小,也就是纳米或埃的量级。

麻省理工公开课 - 化学原理课程节选

These extremely small particles are believed to be linked to comets.

VOA: special.2009.01.20

Now this is mostly irrelevant to what we're talking about except for the fact that there are magnetic particles involved and they're really small because it turns out what's inside most of your laptops and desktop computers are these things called hard drives.

其实这与我们现在谈论的话题没什么关系,除了这里的磁性粒子有关系外,它们是很小的因为它们要放在,你的笔记本电脑或者,台式机中被称为硬盘的里面。

哈佛公开课 - 计算机科学课程节选

These can be sulfate,nitrate, ammonia,sodium chloride and if these are small particles they can be dangerous because if they are inhaled they can reach the lungs."

VOA: standard.2010.04.16

I can see footprints of my boots in the small,fine particles.

VOA: special.2009.07.15

If dark matter particles exist, scientists say, they should be able to observe a small amount of light given off when they hit the nucleus of a xenon atom.

VOA: special.2009.07.21