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

Remember, "is it okay" must always be followed with either "if" or "to".

记住，使用“is it okay”时后面一定要跟上 "if" 或者"to"。

Is it okay 课堂 - SpeakingMax英语口语达人

So, that's the difference in thinking about different types of ionization energy, so it can get a little bit confusing with terminology if you're just looking at something quickly, so make sure you look really carefully about what we're discussing here.

所以，这就是我们,在思考不同类型的电离能时所看到的不同，因此如果你看得不够仔细的话,你可能会被其中的术语弄迷糊了，所以一定要看仔细,我们讨论的是什么。

麻省理工公开课 - 化学原理课程节选