Together,these two shapes create a very strong, light-weight rounded structure.

VOA: special.2010.05.30

So up to this point, before it was really established that yes, light is like a particle sometimes, there was this very strong distinction between what is light and what is matter.

所以关于这个观点，在它被真正确立之前，光有时候像粒子，在什么是光和什么是物质之间,有一个非常巨大的区别。

麻省理工公开课 - 化学原理课程节选

It is light as a feather but strong as steel.

VOA: special.2009.10.30