Punctuation.
The most important fact about punctuation is that it gives order and clarity to the written word. The ommission, overuse, or careless placement of punctuation marks can sabotage the meaning of the text and, at the very least, frustrate and confuse the reader. Ultimately, the successful use of punctuation depends on a solid grasp of sentence structure. Recognizing sentences, clauses, and phrases determines where and how we will place periods, commas, semicolons, dashes and parentheses. Although the use of the more "mechanical" marks - quotation marks, question marks, exclamation points - is a matter of remembering a few basic conventions, the conventions themselves rest firmly on the syntax of the sentence.
Modern newspaper style favors a more streamlined type of punctuation, typically in the dropping of commas and the conservative use of the semicolon and the colon. Literary and scholarly works still rely on the full range of punctuation marks, though perhaps using the comma less often than in the past. Despite the traditional "rules" and suggestions about punctuation, many times the choice of which mark to use - a comma or a colon; parentheses or dashes - comes down to what the writer intends to suggest by one mark rather than another or simply prefers for no easily explainable reason.

The following punctuation guide covers the common punctuation marks in English:


CAPITAL LETTERS
PERIOD
SEMICOLON
COMMA
COLON
DASH
PARENTHESES and BRACKETS
QUOTATION MARKS
EXCLAMATION POINT
QUESTION MARK
THE BAR




The Capital Letter
All sentences in the English language begin with a capital letter. This important punctuation lets us know when the sentence begins. The only time a capital letter is used as punctuation within a sentence is after using quotation marks: you must capitalize the first letter in the first word after the beginning quotation mark.

An Important Consideration for Poets
For many centuries it has been conventional in the
printing of English poetry to print a capital letter at
the beginning of each individual verse. This is done
without regard to sentence structure and no end of
line punctuation is needed unless called for by the
structure of the sentence itself.




The Period:
The period ( . ) is often regarded as a "strong" punctuation mark because it indicates the end of a sentence or a thought that is treated like a sentence for emphasis: {Example: How many people came to the party? Seven.}
One of the most common trouble areas in written English is the run on sentence, in which two or more thoughts are combined without intervening punctuation.
{ Example: We walked down to the boardwalk that we had found on a previous excursion our expectations of a colorful day were not to be disappointed we found many booths that offered a variety of wares and amusements.}
There are many ways to interpret this jumble of information correctly, one of which might be :
{ ' We walked down to the boardwalk that we had found on a previous excursion. Our expectations of a colorful day were not to be disappointed. We found many booths that offered a variety of wares and amusements.'}
Another common mistake in this area is to punctuate a run-on sentence with a comma instead of a period.
{Example: I went to the doctors today, the office was closed due to the holiday.}
The better choice is a period after ' today'.
[Do not confuse the period with the abbreviation point or the decimal point. Neither of the former are punctuation marks and do not mean the end of a sentence; even though the abbreviation point when used at the end of a sentence automatically becomes a period with no extra punctuation needed.]



The Semicolon.
The semicolon ( ; ) is probably the most sophisticated of all the punctuation marks. Like the period, it strongly separates word groupings. Yet it also keeps these groupings closely linked in the same sentence. The semicolon functions in various ways.
(1) To separate the independent clauses in a compound sentence:
{I have a lot of work to do today; I should really get started early.}
Although the two statements could easily be written as two sentences, the close connection of the thoughts makes the semicolon appropriate. The semicolon usually takes the place of the coordinate conjunction (traditionally preceded by a comma) that would otherwise join two independent clauses:
{ I forgot to mail your letter, but I'll do it first thing tomorrow.}
With the semicolon:
{ I forgot to mail your letter; I'll do it first thing tomorrow.}
When at least one of the independent parts of a compound sentence has a subordinate clause in it, both the conjunction and the semicolon may be used:
{It was raining when the game started; but by halftime the sky had begun to clear.}
When the second clause of a compound sentence is introduced by 'moreover', 'however', 'that is', 'furthermore', ect., the conjunction is customarily followed by a comma:
{I thought I had covered the subject in depth; however, there were students who still had pertinent questions.}
(2) To separate parallel clauses or strings of phrases, especially when they have subordinate clauses in them:
{ My favorite holidays are; Valentines, because it centers on love; Easter, because it is centered on hope; Christmas, because it is centered on joy.}
The semicolon may also be used to separate an independent clause from a phrase or a dependent clause introduced by an adverbial construction:
{On vacation last summer we went to some amazing places; for example, Mt Rushmore in the Dakota 's.}



The Comma.
This mark ( , ) serves a number of purposes.
(1) To set off introductory words, including terms of direct address, and phrases: {Ladies and gentlemen, we have a winner.}
(2) To set off words and phrases in series:
{Today's special includes soup, a sandwich, a beverage, and dessert.}
{You can park the car on the street, in the driveway, or in the garage.}
In these examples the comma before the conjunction is called the series comma. In the modern American usage it is often omitted:
{You may run, walk or lift weights.}
(3) To separate two independent clauses when the conjunction is expressed or to set off a series of short or simple independent clauses:
{We have found many good restaurants here, yet I still do not like this town.}
{Feeding the stock, milking the cows, tending the calves were all chores that we completed before breakfast.}
(4) To set off dependent clauses that precede a main clause. Such clauses are introduced by 'when', 'if', 'although', 'after',' where' and other subordinate conjunctions.
(5) To set off dependent clauses within a sentence, interpolated expressions, and word and phrases in apposition:
{He expected, for the most part, that his decision would be approved.}
{ The desk clerk, who always greeted them by name, handed over the key in silence.}
(6) To indicate the ommission of words in sentences containing independent clauses. In the following passage the commas after the names Joe and Lisa indicate that the auxiliary verb 'was' has been omited.
{I surveyed our little group. Mike was sprawled lazily in the old arm chair; Joe, camped in front of the fireplace; Lisa, sitting at the table preparing to write a letter.}
(7) To set off the words that introduce or identify the speaker of a quotation from the quotation itself:
{"Welcome home," he declared, "we have missed you."}
for more information on this see 'Quotation marks'.




The Colon.
The chief use of the colon ( : ) is to introduce text that explains or amplifies what has just been said.
{The dispute involved serious issues: titles, boundary lines, right of way, and the status of tenants.}
When a full sentence follows a colon, it may or may not be capitalized, depending on the writer or the style preferred by the publisher.
When a motto, an adage, or a slogan follows a colon, the first word is capitalized. The colon is also used to introduce longer quotations or those not preceded by 'said', ' remarked', ect.
{ I remember the words of my dear friend, Alec: "Many people spend their lives pursuing wealth and the collection of vast amounts of material goods; only to discover that fate has removed their ability to enjoy what they have accumulated."}


The Dash
This is a punctuation mark that should be used carefully. A dash ( -- ) is a device for separating some portion of a text from the words around it, usually as a means of explaining something. Any text set off by dashes is likely to be read with a sense of emphasis. When used too freely, the dash soon loses its power to emphasize. A piece of writing that is full of dashes can seem hasty and disjointed. The text to be set off must be preceded and followed by a dash unless that text ends or begins a sentence. It is important to place the dashes correctly. In modern usage the dash is not combined with the comma, semicolon, or colon, but in older samples you will find that such combinations are common. Question marks and exclamation points should be retained in the text set off by the dashes:
{ The whole family - all one hundred and fifteen! - were gathered in that one room.}
(Remember; the things inside the dashes are not capitalized even if they are complete sentences.)
The dash is also used to indicate incomplete sentences and breaks in thought. When so used, it is not followed by any punctuation except quotation marks if appropriate.
{"I am sure they will not catch us if we are quiet." Jessie remarked thoughtfully. "How can you be so -- What do you mean us?" Demanded John.}
(Remember: do not confuse the dash with the hyphen. The hyphen is not a punctuation mark. It is used in spelling only: to connect small words into larger ones. 'Two-year-old' or 'Twenty-three' are examples of this function.)




Parentheses and Brackets.
Traditionally these marks, ( ) and [ ], have been reserved for text that in some way explains or adds to the main text.
(1) Parentheses usually enclose commentary or elaboration by the writer of the material in which they appear. Such matter is usually not essential to the structure of the sentence, but its presence may be an important ingredient in the writer's style or the handling of the subject. When a declarative sentence is enclosed in parentheses within a sentence, it does not take an initial capital or end punctuation. However the first word of adages, mottoes, ect., is frequently capitalized, though the period is dropped:
{She embroidered her favorite saying (Well begun is half done) on a pillow.}
When the text inside the parentheses is a question or has an exclamation point, no capital is used but the end punctuation is retained:
{Ann took over the job (she's such a good sport!) when Tom caught the flu.}
It is important to distinguish between a full parenthetical sentence within a sentence, as described above, and an independent sentence that happens to be set in parentheses. An independent sentence in parentheses has an initial capital and end punctuation that must fall inside the closing parenthesis. Parentheses also contain references to pages, chapters, illustrations, and so on.
(2)Brackets enclose information supplied by an editor or author for a text written by someone else. These devices are likely to be needed where quoted text has been shortened; where it contains unfamiliar or difficult terms, misspellings, incomplete identifications, references not readily understood, ect,; or when the editor or author wishes to stress, by means of italics or under scoring, a part of the quotation not emphasized by the original author. Misspellings on the other hand, are indicated by the word 'sic', usually in italics. Editorial emphasis is indicated by the words 'emphasis added' or 'italics mine', or something similar. Stage directions are often put in brackets, especially in Shakespeare's plays.




The Quotation Mark.
These marks are used to enclose the exact words or thoughts of an individual, to set off expressions that require emphasis for various reasons, or to designate the titles of certain literary and artistic works. Quotation marks are in American usage a pair of small symbols ("..."), in British usage often a single symbol ('...'), put at the beginning and end of the quoted text. In American style the single quotation mark is used most often to set off anything quoted within a quotation. In British style it is the opposite: dual quotation marks within the single marks. The single quotation mark may also be used in place of the double mark for special purposes, as in newspaper headlines or in a work of philosophy or language that must define terms precisely. The placement of quotation marks themselves is not usually a difficult matter, so long as you know the extent of the quotation. But combining quotation marks with other marks can be troublesome.
Here is how to use quotation marks with other punctuation.

With the Period.
The period is always placed inside the closing quotation marks. In British usage the period is place outside the closing quotation mark.
With the Comma.
The comma, which separates the quoted text from the words that introduce or surround it, must always fall inside the closing quotation marks.
With the Semicolon.
The semicolon is always placed outside the closing quotation marks. The period that normally ends a full-sentence quotation is omitted when the quotation is followed by a semicolon.
With the Colon.
Like the semicolon, the colon falls outside the closing quotation marks. When a full-sentence quotation is followed by a colon, the period for that sentence is omitted.

With the Dash.
Unlike the colon and the semicolon, the dash may fall within the closing quotation marks, provided it is part of the quotation. A typical instance of this is when the dash is used in dialogue or other quoted text to indicate choppiness, abruptness, or an incomplete thought. Punctuation is not used after a dash that ends a quotation, even if the quoted matter is a complete sentence itself or if it falls at the end of a full sentence. When the dash is not part of the quotation, it falls outside the question marks.
With the Question Mark.
Like the dash, the question mark falls inside the quotes when it is part of the quoted text, outside of them when it is not.
With the Exclamation Point.
As with the question mark, the exclamation point goes inside the quotes when it is part of the quote in the text, outside them when it is not.



Exclamation Point (or Mark)
This mark ( ! ) is used to express a high degree of emotion, emphasis, or excitement. Like the dash and italics, it can lose its effect rather fast if applied to a text too liberally. The exclamation point is considered somewhat stronger than the question mark, so that when both would be appropriate in a text, it is generally better to omit the question mark in favor of the exclamation. The exclamatory 'oh' may be followed by an exclamation point or a comma (but sometimes neither), depending on the degree of emphasis desired; the O of direct address should stand without punctuation:
{Oh! You startled me! Oh, let's forget the whole thing!}



Question Mark.
This mark (?) is probably, next to the period, the most straightforward punctuation mark in English, because it follows a direct question. Yet there are several situations where its use can pose problems.
(1) Within a declarative sentence.

A question should be punctuated within a sentence that is not itself a question.
(2) With a series of questions within the same sentence.

The question mark should be repeated with each change of phrase.
(3) With indirect questions.

No question mark is used with the indirect question.
(4) With the polite request or suggestion.

The polite request, although it sounds like a question, ordinarily takes the period, not the question mark. At the writer's discretion, however, such a sentence can be punctuated as a question, depending on the context and emphasis desired.




The Bar.
This mark ( / ) is extremely rare (outside of computer languages) and is rarely understood. The only valid use, in English, of this mark as punctuation is as an indicator of the point at which a single verse of a poem is completed when the poem is written as prose. This mark is not used when a poem is written as verse. Once again: this mark ( / ) may be used at the end of each line of a poem when the poem is written as prose, usually within a body of prose, and often as a quote within a passage of prose.