他认为，远在公元前30,000年以前，猎人可能会用一套刻在骨头和石头上的符号系统来标记月相。

He believes that as far back as 30,000 B.C., hunters may have used a system of notation, engraved on bone and stone, to mark phases of the Moon.

youdao

是任意的符号系统而非自然符号。

It is a system of arbitrary signs that are not natural signs.

youdao

瑞士语言学家索绪尔认为语言是一个能表达思想的符号系统。

Swiss linguist Saussure thought language is a sign system to express thoughts.

youdao

That is to say, it is not a system of signs understood as stable relationships between a concept world and a world of signifying.

也就是说，它不是一个符号系统，这个符号系统被理解为,概念世界和指示世界间的稳定的关系。

耶鲁公开课 - 文学理论导论课程节选

All of that somewhat complicates the picture, but at the same time, I think you can see that there is a connection between those semiotic systems.

这理解起来可能很复杂，但是你们还是能看到,这些符号系统间的一些联系。

耶鲁公开课 - 文学理论导论课程节选

Delta v is positive in this direction here, the work is negative. So work on the system is positive. Work done by the system is negative.

功是负的，总而言之,外界对系统做功的符号为正。

麻省理工公开课 - 热力学与动力学课程节选