- [Instructor] So, let's take a look at these answers choices but before we do, let's talk about this
word fresnel for a second. Because I was confused
about it but my colleague, who has a long history
in the theatre world, tells me that in the
US, you don't say the s. You say fresnel, accent on the nel. Anyway. We are trying to figure out
what piece of punctuation should go between purpose and their. Should it be purpose, semi-colon, their as it is in the sentence? Should it be purpose,
period, capital T their? Should it be purpose, comma, their? Or should it be purpose, colon, their? Well, in order to figure out what piece of punctuation we ought to use, first we should evaluate
what this sentence is. Break it down into its component parts. So we've already got these
aforementioned fresnel lenses. Well, we know that this is a subject. So we've got fresnel
lenses, that's our subject. What's the verb that they take? Are. Okay. So there's our verb are shaped. And then we're going to be
looking for another noun that has a verb. Oh, there's another one. Rings. And then here's another verb, amplify and concentrate. So we've got a subject verb,
punctuation, subject verb. And so what we're looking at here then is two independent clauses. So I'll bracket them off. So we're looking for one answer for a piece of punctuation
that doesn't work. All the other answer choices should be able to unite
independent clauses. So we're looking for the one outlier. The one thing that can't do that. So, okay. So option A. Semi-colon. What does a semi-colon do? It unites independent clauses. So right off the bat, we can say, alright, knock this one out. We know that this works
so it is acceptable. We're looking for something
that's not acceptable. Option B. Purpose, period, capital T, their. Well, so if we know that
fresnel lenses are shaped in a specific way and for
a very specific purpose, is a an independent clause. Remember that an independent clause can also just be a sentence. That is, in fact, why
they are independent. So if this is a sentence, and this is also a sentence, then there's nothing wrong
with dividing them up with a period and capitalizing
the first letter of their. So, that checks out to me. Answer C. Well, now this is curious. We've got this comma here and we've got two independent clauses and we know that commas cannot
unite independent clauses on their own. They need to be combined
with a coordinating or a fanboys conjunction. That's the conjunction for,
and, nor, but, or, yet, and so. And if you use a comma, plus a coordinating or
fanboys conjunction, you can combine two independent clauses. But if you don't, if there's no fanboys, if it's just a comma on its own, that results in what
we call a comma splice, which is ungrammatical. So right now, option C is looking like it might be our choice. Well, but let's see if we can
eliminate answer choice D. Let's not jump to any conclusions. So this one uses a colon. Purpose, colon, their. Well, what are the powers of a colon? We know that the colon has
the power to introduce things. How do you do? I'm the colon. The colon can introduce. Lists, rather like this one. Descriptions. Explanations or quotations. And also in order to use a colon, and a colon has to follow
an independent clause. So what we're looking at
here is an independent clause connecting to another independent clause. That's not a list, but it is kind of a
description or explanation. Fresnel lenses are
shaped in a specific way and for a very specific purpose, colon, their concentric rings
amplify and concentrate light. So it describes their
shapes, concentric rings. And it describes why, the purpose for amplifying
and concentrating light. We're kind of using this
punctuation mark the colon as an accelerating agent, right? We set up in this first independent clause that fresnel lenses have
these particular properties and then we use the colon
to build the momentum into the second independent clause. And so what does this mean? It means that we can use colons, which means we can knock out this answer, which means that C is our correct choice. When you're given a punctuation question, like this one, the first thing to do is to figure out the context of the sentence. You know, how many independent clauses or dependent clauses are you working with. Because that can change the landscape, and that can change the
appropriate punctuation to use in that scenario.