You take a material like silver and put it in a glass case and that's the definition of a meter.

你拿某种材料,比如银,把它放进玻璃柜里,那是一米的定义

耶鲁公开课 - 基础物理课程节选

I didn't put that down, so just in case The Greek word synkresis means "a mixing together."

这个我没写在讲义上，我写黑板上,希腊语Synkresis意思是“融合“

耶鲁公开课 - 新约课程节选

So in the first case of this first bond here that I've put in a square, what type of a bond is this, is the sigma or pi?

在这第一个键里,我用方框把它标出来了，这个键是什么类型的，sigma还是π？

麻省理工公开课 - 化学原理课程节选