Over the centuries, people have commented that I have a knack for explaining grammar. Now, I do not profess to be a grammar expert by any means, but I will begin a regular grammar feature on this blog. I will mostly be using explanations I used with my junior high students eons ago and the lessons I use to teach my two homeschooled sons.Today I bring you Freight Train Sentences , otherwise known as How to properly punctuate a compound sentence.A compound sentence is two simple sentences joined together. At this point, my eleven year old would say, “Wouldn’t it be easier to just keep them separate!” Well yeah, but then all our sentences would be about the same length which would hamper the flow and readability of our writing. And it would be boring. Very, very boring.

Following are two complete simple sentences. They each have a subject and a predicate along with various modifiers. Each of these sentences is like a train. If you are going to hook them together, you need something strong enough to hold them. Otherwise, they’ll run together. Kabam!

Hortencia loved to dine at dimly lit Chinese restaurants.
Alvin preferred the salmon patties at Joe’s grill.

If the two sentences are combined this way – Hortencia loved to dine at dimly lit Chinese restaurants Alvin preferred the salmon patties at Joe’s grill. – you would have a run-on sentence.

A comma (,) is not enough to keep these two trains apart. Hortencia loved to dine at dimly lit Chinese restaurants, Alvin preferred the salmon patties at Joe’s grill. This construction is known as a comma splice. Sure, there’s “some” punctuation, but a comma isn’t strong enough to hold these two sentences apart.

Also, a conjunction alone is not enough to keep the two sentences apart. Hortencia loved to dine at dimly lit Chinese restaurants but Alvin preferred the salmon patties at Joe’s grill. This example is also incorrect.

In order to properly combine these two sentences you need a comma AND a conjunction.
Hortencia loved to dine at dimly lit Chinese restaurants, but Alvin preferred the salmon patties at Joe’s grill. The most common conjunctions are “and,” “but,” and “or.”

OR

You can also combine two compound sentences with a semi-colon (;).

Hortencia loved to dine at dimly lit Chinese restaurants; Alvin preferred the salmon patties at Joe’s grill.

Summary: Think of complete simple sentences as freight trains. If you are going to hook them together, you need something strong enough to hold. Choose either a comma/conjunction combo or a semi-colon.

 

** This is an older article, originally published on my Live Journal blog.