Hello, dear readers! While I’ve taken some time off from writing, I have continued to actively search for public errors. I’ve acquired a plethora of photos, and I’m glad to be back. My hope is to post weekly (ish) and get back on track with consistent writing. After all, the world needs educated about all these errors! Readers, be warned: This post is a bit lengthy and (somewhat) complicated. Let’s dive in.
I found this error on a mall advertisement on my way to Urban Outfitters. It’s a tricky one that can be (and is) often overlooked. The poster seems grammatically sound: We have two independent clauses joined by a comma and coordinating conjunction. All is good, right? Not quite.
The issue we have here stems from the word so. As many of you know, so is one of the coordinating conjunctions (for, and, nor, but, or, yet, so). But, the tricky little bugger is quite versatile and can also be a subordinating conjunction (a conjunction that introduces a subordinate clause*), as it is here.
The key difference in understanding the two lies in the meaning. If so is a synonym of therefore, it is serving as a coordinating conjunction and should have a comma preceding it. However, if so is conveying the meaning so that, it is a subordinating conjunction. A comma in this instance, therefore, would be incorrect.
Let’s take a look at two sentences for illustration. The first uses so as a coordinating conjunction, the second, subordinating.
- I broke my ankle, so [therefore] I can’t walk.
- I write grammar posts so [so that] my heart can be content.
Since so is a coordinating conjunction in the first sentence–and is joining two independent clauses–we need a comma. So, in the second sentence, is a subordinating conjunction–no comma necessary.
If the distinction remains clear as mud, here is another way to identify so as a subordinating conjunction. If the clauses can be reversed–and the sentence remains logical–you have a subordinating conjunction. Let’s see if this works on our first sentence:
- So I can’t walk, I broke my ankle.
Heavens no! This doesn’t work at all. The logic breaks down. I did not, after all, break my ankle to keep myself from walking. Clearly, this sentence does not contain a subordinate clause. How about sentence #2?
- So my heart can be content, I write grammar posts.
Indeed, it works! The reason I write grammar posts is so that my heart can be content. The so in this sentence is serving as a subordinating conjunction.
And now you’re thinking, “What’s this crazy lady talking about? She put a dang comma in the sentence!” Yes, my friends, I did–but for other reasons. We have reached Part II of this lesson: Punctuating Subordinate Clauses. You see, if a sentence begins with a subordinate clause, you MUST place a comma between the dependent clause* and independent clause*. However, if the sentence begins with the independent clause, you DO NOT place a comma between the two clauses. Let’s look again at our sample sentence:
- I write grammar posts so my heart can be content. [IC DC]
- So my heart can be content, I write grammar posts. [DC , IC]
This rule might be a bit confusing; it certainly was for me the first time I came across it. But by practicing–and analyzing these types of sentences–it will become second nature, and you, too, can determine whether to use a comma.
Let’s take a final look at the poster containing the error. The so in the sentence means so that, not therefore. And if we wanted, we could switch the clauses: So they can thrive later, we help children early. (Note the comma here!) Since the sentence in the poster begins with an independent clause, it should not contain a comma. Here is my suggested revision, equipped with punctuational perfection: We help children early so they can thrive later. That’s much better.
*Subordinate Clause: a type of dependent clause that is introduced by a subordinating conjunction
*Dependent Clause: contains a subject and a predicate; cannot stand alone as a sentence
*Independent Clause: contains a subject and a predicate; can stand alone as a sentence
Michelle Lingo 