If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:4:46

Subject-verb agreement | Worked example

Video transcript

- [Instructor] The NFPA 704, also known as the fire diamond, is a hazard identification system used by emergency responders that consists of a four-chambered diamond with numerical rankings corresponding to flammability, chemical instability, and poison. This is quite a complex sentence. It's got a lotta chunks. And to aid us in figuring out what the deal is with this question, which is an error ID question, we've got all these underlines, we've got these five underlines. Given that we know that, in that spirit, let's simplify the sentence as much as possible. We can do that by taking out any extraneous information. So also known as the fire diamond, this is a comma-bounded descriptive aside, we can knock that guy right out, voop, there he goes. Is a hazard identification system, really all we need to know is that it's a system, so I'm gonna take our hazard identification system. Used by emergency responders, sure that's a noun phrase, we'll say that's all one thing together. That consists of a four-chambered diamond, and then with numerical rankings corresponding to flammability, chemical instability, and poison, that's all one long non-essential prepositional phrase. I will point out before I cross it off that flammability, chemical instability, and poison is a lovely example of parallel structure. These are three lovely nouns in a row. But we don't need them for the purpose of finding the core of this sentence, so I'm just gonna go goodbye to with numerical rankings corresponding to flammability, chemical instability, and poison. What's our sentence now? Oh and let's take out four-chambered. I don't need to know how many chambers the diamond has. The NFPA 704 is a system used by emergency responders that consist of a diamond. Now to me, consist jumps out right away now that I have the NFPA 704 is a system used by emergency responders that consist of a diamond. There is a disconnect between the singular conjugation is, the singular noun system, and the plural conjugation consist. If consist were to line up with system, it would be consists of with an s because that would be the singular conjugation. So what we're look at here is a subject-verb agreement question. And what does agreement mean? It just means that the number, the grammatical number, of the subject and verb have to align. And number is just another way of saying singular versus plural. So this is our answer, and in order to answer this question, you wouldn't even need to say how you would fix it. That's something for a revision style question. For error ID, you just say, that's incorrect, I've got it, and you move on. But for our purposes for this video, I think it's important to say why it is incorrect. And we can go back through the other choices and indicate why they don't contain errors. So real quick, option A, this comma is being used to set off this descriptive aside. We've got these two commas here that are bounding off this descriptive phrase, also known as the fire diamond. That is standard usage. So, cross that off. Is, right we flagged this earlier as a singular verb that agrees with the singular word system or NFPA 704. NFPA 704 is kind of ambiguous, but we know that since the rest of the sentence calls it a system, a singular system, that is also makes sense within the sentence. That exhibits proper subject-verb agreement. Used by, this is a conventional expression. Used is an adjective that is modifying the word system. This checks out. And since we've identified that there is an error, consist, we're gonna cross off no error because there is an error. So whenever you can, if you encounter a very complex sentence like this with a lot of moving parts, try to find the core of the sentence. To quote Li Shang in the legendary film Mulan, once you find your center, you are sure to win. Peel away the unnecessary descriptive asides like this or the unnecessary noun phrases or adjectives or prepositional phrases, and that will leave you with the heart of the sentence. And that will make it easier to say, okay, do the verbs exhibit agreement in number? Do they have some unexplained shifts in verb tense? So that's your strategy is you wanna make sure is just get rid of everything that is inessential. And that's the way you do it.