One of the few concepts taught after fourth grade about writing is the semicolon, that mysterious mis-matched mark of mangled sentences. Some teachers ban its use entirely because some students use it too liberally, as if they had a semicolon shaker to scatter over their compositions. Where then, should you use a semicolon, and why?

Use a semicolon to attach a complete sentence to the end of another complete sentence:

1. when the second sentence is closely related to the first

2. when you want the sentences to have equal weight

3. when you want to elevate the tone of the writing to a more formal stance by using longer sentences.

Sentences joined with a semicolon are said to be "compound" having two equal parts.

The lower half of the semi-colon in a period. It works the same way as a period, showing that the end of a sentence has been reached, and that a new sentence is beginning. It implies that there is a relationship in the ideas of each part; it does not state the nature of that relationship.

The same thing can be accomplished with a comma and a conjunction: for, and, nor, but, or, yet, so (mnemonic: FANBOYS).

I went to the store. It was closed.

I went to the store; it was closed.

I went to the store, but it was closed.

Usually at this point, another concept is added to the mix: conjunctive adverbs.

A conjunctive adverb shows some relationship between the two equal sentences: however, nevertheless, consequently, therefore. These adverbs are no less evil than any others; therefore, they should be restrained by commas to keep them from contaminating the rest of the sentence. Their lack of grammatical relationship to the other parts of the sentence is shown by the ability to appear in different positions, always separated by a comma:

I went to the store. However, it was closed.

I went to the store; it, however, was closed.

I went to the store; it was, however, closed.

I went to the store; it was closed, however.

Using a semicolon does not require the use of a conjunctive adverb.

Much of the confusion about comma splices and run-on sentences is caused by the confusion of complete sentences with dependent sentences. Dependent sentences form a pattern called "complex" with at least one dependent part and one complete part. As we know from life, unequal partnerships with dependents are always complex.

If you take a perfectly good sentence (I went to the store) and add a dependent word (When) to the beginning, the resulting sentence is no longer independent:

When I went to the store...

You might argue that you could say that as an answer to a question, but the word "when" tells us that more is coming to explain what happened at that time.

A comma is used at the end of this dependent part to let us know that the main part of the sentence is beginning:

When I went to the store, it was closed.

These two sentence parts are not equal, so you would not use a semicolon. In fact, if the first part were at the end of the main part, no comma would be needed because the word "when" announces the next section.

The store was closed when I went to it.

This dependent sentence pattern is the reason students create comma splices (using a comma where only a semicolon may tread). Since students learn the complex pattern first, they sometimes get the idea that only a comma is needed in the middle of a sentence regardless of the meaning or structure. They do not understand that the parts are not equal and independent.

Now that you know the secret code of the semicolon, you are armed with a plan. If you are not sure whether to use the semicolon, use a period to make two sentences. If that works, you can use a semicolon. Then if you wish, you can add a conjunctive adverb and comma after the semicolon like a cherry on top of whipped cream; alternatively, you can use the mundane comma and conjunction.

Just remember to look for a complete sentence on each side of the semicolon.

Looking for more ideas on how to get better grades on your writing or fewer sneers from your colleagues? Visit Charlotte Babb at her website: http://charlottebabb.com Her twenty years of teaching high school and college, online and on ground, have not yet deprived her of hope that everyone can learn to write well.