A subordinate clause can either precede or follow its main clause. What writers tend to get confused about, however, is when and where to place commas in relation to subordinate clauses.

The simple rule is this: If a subordinate clause precedes the main clause, separate the two with a comma:

Unless you have a lot of money, steer clear of Rodeo Drive.

If the subordinate clause follows the main clause, no comma is usually needed:

Steer clear of Rodeo Drive unless you have a lot of money.

Many writers wouldn’t be able to resist the temptation to stick a comma between Drive and unless even though it’s not strictly necessary. There’s a natural pause that seems to call for a comma, but try to resist its call unless a pause is needed for special emphasis.

One notable exception is when the subordinating conjunction because is used and the main clause expresses a negative concept:

Don’t worry about your spelling errors because the editor will fix them.

Omitting a comma in this sentence suggests the meaning that there’s another reason not to worry about the spelling errors:

Don’t worry about your spelling errors because the editor will fix them; worry about them because you shouldn’t have made them to begin with.

So if the real reason you shouldn’t worry about the spelling errors is, in fact, because the editor will fix them, we need a comma:

Don’t worry about your spelling errors, because the editor will fix them.

Watch out for because in your subordinate clauses. Scrutinize your sentences to make sure you’re not clouding the issue and confusing your readers.

Most of us are familiar with hyphens and their uses. They’re used to form compound modifiers (such as in “a well-attended event”). We also use them to break a word that falls at the end of a line. This usage is becoming less common, however, because word processing and layout software programs typically have automatic end-of-line hyphenation features.

En and em dashes are less understood. The en dash is the width of a capital N (hence, its name). It’s used to indicate a range, as in the following examples:

For your homework, please read pages 162–195.

The meeting will be on Thursday, 4:00 p.m.–6:00 p.m.

The artist’s blue period, 1948–1952, was his most productive.

En dashes are also used to connect a prefix with an open compound:

post–World War II

ex–vice president

The reason for using an en dash with such compounds is to send a subtle signal to the reader that the prefix belongs to the entire compound, not just the first word of it.

Em dashes are the width of (you guessed it) a capital M. Most often, they’re used in pairs to emphasize an element or elements within a sentence:

Cruciferous vegetables—broccoli, cabbage, and cauliflower, for instance—are said to lower the risk of cancer.

Em dashes can also show an abrupt change in thought:

I thought I had time—more than enough time—to catch the train.

Or they can show interrupted dialogue:

“I told you I can’t—”

“You mean you won’t, not can’t,” she said.

Many writers use a double hyphen in place of an em dash, and you might have noticed that your word processor sometimes will automatically turn them into an em dash. Most word processors have shortcuts for creating en and em dashes. It would be worth your while to search your help menu to find out what they are.

Although often taken for granted, the question mark can be used for more than ending a direct question. Really? Yes.

The question mark was first seen in the eighth century when it was called the punctus interrogativus. There are many theories about the origin of the symbol, which has changed several times before settling on its current form in the eighteenth century. For example, the Latin word for question is quaestio, which was abbreviated to ‘Qo’ in the Middle Ages. It’s thought that the modern symbol represents the ‘Q’ placed over the ‘O’.

Regardless of its origin, the question mark can be used in a variety of ways. One such use is to end a verb-less sentence. Although verb-less sentences may not be considered proper sentences in some circles, they are used quite frequently. Some examples include:

• What?
• When?
• Where?
• Really?

Ending a tag question is another use for the question mark. A tag question is a statement that is followed by a question, such as:

• He left early, didn’t he?
• The recipe calls for one cup sugar, right?

In a sentence containing a series of questions, you may include a question mark after each. Be careful with this type of writing. Although the use of a question mark is accepted, readers may find a long string of questions confusing.

• Who saw the victim last? Her husband? Her son? Her daughter?
• Which way are we supposed to turn at the corner? Right? Left?

Two places where the question mark should not be used are at the end of indirect questions or courteous requests. Although these types of sentences may seem to be questions, they do not require the use of the question mark.

• I asked my son if there were any messages.
• Will you please reply as soon as possible.

Although the choice to use the question mark us usually a fairly easy decision, some situations like these can make you think twice.

You can follow Steven on Twitter @drumming4you.

We’re going shopping, out to dinner, and then to a movie, too.

But is that comma really necessary? “Too” in this context means “also,” but you’re not likely to see the sentence written like this:

We’re going shopping, out to dinner, and then to a movie, also.

No one seems to know how this particular quirk started, but it’s firmly entrenched in our over-cluttered writers’ brains. Even journalists do it, and modern-day practice is to strip news stories of as many commas as possible without hopelessly obfuscating meaning. Still, that niggling comma before “too” persists.

The editors at the Chicago Manual of Style share their opinion:

Use commas with too only when you want to emphasize an abrupt change of thought:

He didn’t know at first what hit him, but then, too, he hadn’t ever walked in a field strewn with garden rakes. In most other cases, commas with this short adverb are unnecessary.

The bottom line is, there’s no clear rule that either specifies using the comma or forbids it. It’s the writer’s choice. The rules of grammar don’t often allow writers to have choices. It’s kind of nice to be thrown a bone from time to time.

I wrote a sentence:
“Experts teach, peers comfort.”

Word creates an error unless I write
“Experts teach and peers comfort.”
or
“Experts teach; peers comfort.” (semi colon versus comma).  

However, I like the shorter pause by a comma.  Any rules on this?

Punctuation exists to help readers make sense of what is written, but it can also be a means of helping a reader hear the writer’s voice.

The difference between Ron’s preferred sentence and those suggested by Word is a difference of style. All three sentences are understandable, but the first conveys an introspective tone that the others lack.

Julius Caesar’s boast of Veni, vidi, vici is usually translated as I came, I saw, I conquered. The insertion of an and or of semicolons would spoil the effect by slowing it down or making it sound more prosaic than triumphant.

The Chicago Manual of Style staunchly defends the semicolon to separate independent clauses not joined by a conjunction:

Two independent clauses not joined by a conjunction are best separated by a semicolon or a period. This principle has always been the fifth major rule put forth in The Elements of Style—starting with Strunk’s original (Ithaca, NY, 1918) and continuing almost unchanged . . . through the latest (fourth) edition of Strunk and White (New York, 2000).

Strunk, however, doesn’t get the last word, not even in the offices of the CMS. When a writer queried about using a comma instead of a semicolon in a sentence with two independent clauses and no conjunction, the response was that the sentence in question did, in fact, read better with the comma. The CMS editor acknowledged that

[s]ometimes the ear is more important than the rulebook.

When choosing whether to use a comma or a semicolon, the writer must consider both clarity and desired stylistic effect.

Here’s an interesting About article on the semicolon

P.S. I just discovered that the National Geographic Manual of Style supports the comma for short clauses and no conjunction. Their example is also the Julius Caesar quotation. (Item 5)