[? ANGELIA: ?] Yeah. Hi, I'm [? Angelia ?] from Jakarta, Indonesia. 

BRIAN: Nice to meet you. 

ANGELIA: Yeah. My question is, I see, from the [INAUDIBLE], that Brian and David are really [INAUDIBLE] when they are teaching. So my question is how to develop such [INAUDIBLE], like public speaking and teaching CS combining and [INAUDIBLE] and also technical skill. Thank you. 

DAVID: Well, thank you. You're too kind, I think. So one of the reasons I, at least, went into teaching 20 years ago was honestly because I wanted to get better at public speaking. As you may have heard me say in one of CS50's classes, at the time, I had run for the undergraduate council at Harvard, or the student government, if familiar-- student council at this school-- just kids that generally try to accomplish goals on campus. 

And I ran for this election and lost miserably. I did not win the election. And part of that, I do think, was because I was very ineloquent at the time. I had trouble conveying my ideas. I performed very poorly in one of the on-campus debates. And so I was really angry at myself that I wasn't better spoken at the time. 

And so I started volunteering as a teacher for one of the undergraduate student groups that allowed me to teach classes to other students, like HTML, and CSS, and other such technologies. I then was a teaching fellow, or teaching assistant, my fall of my senior year of university. And then I was fortunate to be able to teach my own class spring of my senior year. 

And so it really, honestly, was just practice, practice, practice. And teaching, particularly, really helped me organize my thoughts, allowed me an opportunity, again and again, to try to communicate clearly to other people, more so than if you're just giving a speech or just presenting in a class. Having to teach, I think, was really a key ingredient. 

And I think it helped, technically, that I just enjoyed what it was I was teaching. I really enjoyed programming. I really enjoyed computer science on the whole. And so being able to teach something I was passionate about just really helped. Brian, what was the case for you? 

BRIAN: Yeah, I think I would agree with just about all of that. I think that practice is the key thing that helps make you a better teacher. Just getting experience, even if it's just explaining something to a friend or to a peer-- that helps you to start to think about how to take the ideas that might exist in your head and put them a little bit more precisely into words, and, in particular, to be able to explain something in a way that is accessible to someone who hasn't seen the topic before. 

But I often think about, when I was first learning some of the material, the types of explanations that worked and didn't work for me, and trying to come up with explanations that can help to explain very technical topics but, hopefully, in a bit of an easier-to-understand and more accessible way. 

And it definitely helps that the topics that I get to teach are things that I find really interesting. With the artificial intelligence class that was released this month on edX, I had a lot of fun preparing that class and thinking about what topics I wanted to cover, because [INAUDIBLE] all topics that I personally find very interesting and exciting in computer science right now. 

And so the opportunity to be able to teach about those topics and to talk them through in a lot of detail, I found very exciting. And so I hope that does come across in the classes. And I'm glad that you've been enjoying them.