 In mathematical writings, one should watch out for confusing pronouns. I'm saying things like it, this, that. These are all pronouns that could describe almost anything, right? And honestly, this is a confusion in just general English, right? You gotta make sure that your pronoun is clear by context because if the context is insufficient, you can get confusion and we definitely wanna avoid those confusions. Let me give you an example of such a thing. Take the sentence, since x is a subset of y and the cardinality of x is greater than zero, we see that it is not empty. And so in this sentence, it's like, what is it? What is not empty? Clearly we're describing a set, a set is not empty, but what set? X is not empty because its cardinality is not zero, but it's also true that y is not empty because it contains a non-empty subset. So honestly, the statement that it is not empty could apply to both sets, x and y. And so you should clarify which one are you referring to? So an improvement would be since x is a subset of y and the cardinality of x is greater than zero, we see that y is not empty. So it's not that pronouns are bad, by all means, use pronouns when appropriate, but you should always be cautious when you use a pronoun that if you don't have the appropriate context, the pronoun could lead to misunderstandings, it could lead to confusion, therefore it's best to just avoid confusing pronouns in general instead of using words like it to spell it out. Like in this case, it versus y, it really doesn't make the sentence any longer. Like you look at those periods, they look lined up right there, but one removes all confusion whatsoever. So be in that habit of being more explicit in your language and only use pronouns when the confusion is avoidable. That then brings us to the end of lecture 25. Thanks for watching. If you learned anything from these videos, please like them, share them with friends or colleagues if you think they could benefit from them too, if they wanna watch these things. Subscribe to the channel to see more videos like this in the future. And as always, if you have any questions, feel free to post them in the comments below and I'll be glad to answer them as soon as I can.