Within-sentence punctuation | Worked example

- [Instructor] The Darien Gap, a thickly forested region of Central America, separates Panama and Colombia, indigenous people have long resisted building a leg of the Pan-American Highway through the Gap. So here we have an error-ID question we're gonna try and figure out as quick as we can what is wrong with this sentence. And remember, you don't need to know how to fix the error in an error-ID question, all you have to do is flag it and move on. However, Khan Academy being Khan Academy, we will endeavor to tell you how to fix the error, because hey, it couldn't hurt, and I'm feeling generous today. So okay, so option A, the Darien Gap, we have this comma here and that's what's underlined, but we also have another comma here. So this is what we call a comma bounded descriptive aside, you can call an appositive if you want, but what it's doing is it's blocking off this chunk, this description, a thickly forested region of Central America, to refer back to the Darien Gap. So this is being used correctly, so I'm gonna cross it off. This next underline, thickly forested, so this is testing our knowledge of adjectives and adverbs, are they being used correctly? So this is an adverb here, and this, forested, is an adjective. And what's happening is that the word thickly is describing forested, and forested is describing region. This tracks with what we know about how adjectives and adverbs work, gonna cross it off. And now we come to the comma, and this is our error and I'll tell you why. But first I'll say that this is a within-sentence punctuation question. And specifically the kind of error that is being committed here is called a comma splice, which is a kind of error that occurs when you join two independent clauses with just a comma. Follow-up question, how do we know these are two independent clauses? Well, let's look for subject and verbs. So, okay, so here's our subject, the Darien Gap, and here's our verb, separates, that's clause the first. Indigenous people, so people is the subject, have resisted, and that's our verb, right. So we have these two independent clauses, these two things could be sentences on their own. The Darien Gap separates Panama and Colombia. Indigenous people have long resisted building a leg of the Pan-American Highway through the Gap. So we have two independent clauses, two sentences that could stand on their own, united incorrectly by a comma. So there's our error. One of the ways you could fix it, though you don't have to for the purposes of this question, is you could change this comma into a semicolon, or you could keep the comma, but add one of the FANBOYS conjunctions. That's for, and, nor, but, or, yet, so. Also known as the coordinating conjunctions of English. So option C is our answer. Let's look at D real quick, see what the deal is. A leg of the Pan-American Highway. This is a conventional expression referring to using the word leg as a metaphor for part of a route, so a leg of the trip. If the entire trip is meant to comprise the entire body, then a leg of the trip is some portion of it. I don't know the origin of that, but I do know it is a conventional expression in English. So, this is not an error, and then we can check off no error because, hello, we found the error and it is C. If you're uncertain about a piece of punctuation inside of a sentence, do the before and after test, especially if you think there might be a comma splice happening, which is, before and after the comma, is there an independent clause? Is there an independent clause before and after? If so, and if there's no coordinating conjunction, no FANBOYS conjunction following the comma, then that comma is being used incorrectly. Conversely, if you see a semicolon and it's followed by a FANBOYS conjunction, that's redundant, and either you need to get rid of the semicolon and turn it into a comma, or you need to get rid of the conjunction. So if you have doubts about a piece within sentence punctuation, look both ways before you cross off that option, as it were.