It occured to me yesterday in my class that maybe someday there won't be social security numbers anymore, and on birth everybody will be given an e-mail address.

我昨天上课的时候想到,或许有天大家出生时,得到的将不是社会福利号码,而是一个邮箱地址。

麻省理工公开课 - 电影哲学课程节选

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