The Proper Use Of The Full Stop, Comma And Semicolon In Sentences

PUNCTUATIONS
Punctuation can be regarded as guidance to the reader, so the use of capital letters and, in printing, the use of italics are included in this regard.

The punctuation marks in English consist of the following:

Full stop .

Comma ,

Semicolon ;

Colon :

Question mark ?

Round brackets ( )

Square brackets [ ]

Exclamation mark !

Single quotation marks ‘ ’

Double quotation marks “ ”

Hyphen –

Dash —

There are also the apostrophe (’) and mark of omission (…). But, for the moment, I'll discuss on only Full Stop, Comma and Semicolon, the rest shall come later. Please bear with me.

FULL STOP

We all know that the full stop is used at the end of a sentence (anyone who hasn’t known this is needs special training). Full stop should indicate, in fact, that the sentence has come to a stop. Yet too often we come across letters that start like this:

“Referring to your letter of the 30th September.”

This collection of words is not a sentence, and after the full stop the reader is left floundering.

After “September” there should be a comma, followed by the noun or pronoun attached to the present participle “Referring”. A correct construction would thus consist of something like this:

“Referring to you letter of the 30th September, I am happy to say that your work shall be edited.”

An incorrect construction would be:

“Referring to your letter of the 30th September, your work shall be edited.”

This means, quite absurdly, that your work has been referring to your letter.

The Full Stop with Abbreviations

The full stop is commonly known to also denote abbreviations. The modern trend in the UK is now towards an “open” style for abbreviations in which there are few full stops.

It is usual to allow the full stop only to denote those abbreviations which are parts of words and not those abbreviations in which the first and last letters of words are given (contractions); for example, Mr, Mrs, Col (Colonel), Dr, Revd (Reverend), St (Saint or Street), and Rd (Road). Typical abbreviations where a full stop is used are Jan., Sept., Mon., Lag., Gen., Capt., in. (for inches), cm., approx. and Co.

For initials of capital letters that stand for organisations the full stop is very much the exception rather than the rule. BBC is now widely accepted, as are AU, FIFA, KGB and so on. The forms _AD and _BC are rarely seen with full stops these days.

Lower case initials tend to keep their full stops—i.e., e.g., p.m. and the likes.

Incidentally—and unbelievably—if an abbreviation comes at the end of a sentence there should logically be two full stops—the first for the abbreviation and the second to mark the end of the sentence. In practice, nevertheless, it is conventional to make one full stop do for the two, lest your readers call you an eccentric prof..