You always want to check your signs at the and because it's so easy to get the sign wrong, and I was hoping that it was right here because I wasn't sure, but it turned out to be right.

我们完成计算时，一定要记得检查符号,因为很容易弄错符号，刚才我就不太确定,是否弄错了符号，检查发现没有问题。

麻省理工公开课 - 热力学与动力学课程节选

So I can do this really simply with a scale or just with my own arms.

这个比较很容易就能完成，我可以用天平,或者直接用我的手臂就行了。

哈佛公开课 - 计算机科学课程节选