 Okay, so let's do an example of where we're identifying the substituents that potentially could come off a chain, a carbon chain. So I have 17 different substituents that you should know by now and we're going to look at this particular carbon chain where all 17 of them are placed and we're going to identify those particular substituents by the numbers relative to their names, okay? So let me just do this one and then the next one y'all can help me. So I'm just going to go through them one, two, three, four and identify them by ABCD. So methyl group, let's go look for a methyl group. So we see one here at G, right? So this group here is a methyl group, okay? Methylene, remember a methyl group is a carbon with three hydrogens. A methylene is a carbon with two hydrogens coming off. So there's your methylene at C. A methine, of course, is a carbon with one hydrogen coming off of it. So I found it here at D, okay? There's your methine carbon right there. So now we're getting into some of the groups, isopropyl. Well, you should know that one by now that it's here at E, okay? So you see the propyl group, iso means that it comes off of that second problem there, isopropyl does. So that's E, isobutyl looks like an isopropyl group except it's got one more carbon, right? So if you see there, that kind of looks like an isopropyl with one more carbon. So that's a butane. So we call that an isobutyl group, so that's L. So a sec-butyl group, that's going to be another butyl group, right? So four carbons. So if we look around, well, we've got two more, once here, that's the tert-butyl, and the other one's here, the sec-butyl. So sec-butyl is A. Oh, and I gave it away. Tert-butyl is the other one that I showed you, M, okay? Neopentyl, so what does that mean? It's a pentyl group, pentane, five carbons, right? So if you can look around, this one might be harder for you, but the only group that has five carbons in it is one, two, three, four, five, there's your neopentyl group, okay? So it looks kind of like a tert-butyl group with one more carbon in it, so that's what I'm saying. Neopentyl group is where the double bond is connected directly to the substituent or main chain. So if you have a double bond where one of the carbons is connected directly, that's a vinyl loop. So that's F. And allyl group has one carbon in between the substituent and the double bond, so right there, B. Propagyl group, let's see. That one is a triple bond with a carbon attached at the substituent. So the triple bond here has the carbon attached to it, and that carbon is attached as the substituent, okay? So we see, well, there's only one with a triple bond, so kind of obvious where the perpetual group is, so that's H. Phenyl groups, and now we're getting into the benzene rings. Remember a phenyl group is just the benzene ring by itself that's attached, so that we have a B here, I, and then a benzene group, that's a benzene ring with one carbon more, right? So we've got the benzene group here at O, and now we're into our amines, right? So these should be pretty straight forward for you. So primary amine, the nitrogen's connected to one carbon, so it's right there, right Secondary amine, the nitrogen's connected to one, two carbons, so that's P. Atertiary amine, the nitrogen is connected to one, two, three carbons, so that one is K. And then a quaternary ammonium ion, of course the positively charged nitrogen is going to be, okay? So we got all of these ones. There's one or two groups that aren't present on this particular problem that you need to know, so make sure you go over those ones as well, okay? So if there aren't any questions on this, it's pretty straight forward, just a matching one. We can kill the video. Okay.