"We could look for beacons." "It could be that there are alien civilizations that have simply created something a little bit like a lighthouse that sweeps the plane of the galaxy, goes bleep, and it's there to attract attention, or it's a monument, or an aesthetic symbol or even a religious symbol.

VOA: standard.2010.04.16

Remember, all you have to do is fill in the one or two-letter abbreviation for the chemical symbol.

记住，你们只要,用一两个字母的缩写,来代表化学元素就可以了。

麻省理工公开课 - 固态化学导论课程节选

You are required only to put the one or two-letter chemical abbreviation, the symbol.

你们只需要,用一两个字母来代表一个化学元素。

麻省理工公开课 - 固态化学导论课程节选

It's important for you guys to know that everything you write down in the notebook or blackboard as a symbol is actually a measured quantity.

其重要性就在于,你们要知道,你们记在本子上或者写在黑板上的任何物理符号,实际上都是测量量

耶鲁公开课 - 基础物理课程节选