First of all, negative time should not bother anybody; t=0 is when I set the clock, I measured time forward, but yesterday would be t = -1 day, right?

首先,负的时间对我们不存在任何干扰,t=0使我们设定的初始时间,我是用顺序计时,所以昨天就可以记为-1天,对吗

耶鲁公开课 - 基础物理课程节选

And that's how we will,over time, also help what comes off on the negative side.

那就是我们将要致力做到的，同样对克服消极因素，有所帮助。

哈佛公开课 - 幸福课课程节选

The return, of course, in any given time period is the percentage increase in the portfolio; or, it could be a negative number, it could be a decrease.

当然了，收益率是一定时间内,投资组合的增长率;,也可能是一个负数，表示负增长。

耶鲁公开课 - 金融市场课程节选

Convention, OK, this negative sign is just a pure convention. You just got to use it all the time. If you use an old textbook, written when I was taking thermodynamics, they have the opposite convention, and it's very confusing. But now we've all agreed on this convention, and work is going to be with the negative sign here.

系统对外界做功的符号为负,这就是我们,在本课中的规定，纯粹出于统一符号的需要，有些教科书中，可能会使用相反的符号规定,注意不要混淆了，这门课上,我们将一直使用。

麻省理工公开课 - 热力学与动力学课程节选

So, let's say we start off at the distance being ten angstroms. We can plug that into this differential equation that we'll have and solve it and what we find out is that r actually goes to zero at a time that's equal to 10 to the negative 10 seconds.

也就大约是这么多,所以我们取初始值10埃,我们把它代入到,这个微分方程解它,可以发现，r在10的,负10次方秒内就衰减到零了。

麻省理工公开课 - 化学原理课程节选