The Elements of Style, Fourth Edition

Follow this rule whatever the final consonant.

1. Form the possessive singular of nouns by adding 's.

Restrictive clauses, by contrast, are not parenthetic and are not set off by commas.

The abbreviations etc., i.e., and e.g., the abbreviations for academic degrees, and titles that follow a name are parenthetic and should be punctuated accordingly.

The number of the subject determines the number of the verb.

When the subject is the same for both clauses and is expressed only once, a comma is useful if the connective is but. When the connective is and, the comma should be omitted if the relation between the two statements is close or immediate.

Two-part sentences of which the second member is introduced by as (in the sense of "because"), for, or, nor, or while (in the sense of "and at the same time") likewise require a comma before the conjunction.

Use a dash only when a more common mark of punctuation seems inadequate.

Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the

The colon also has certain functions of form: to follow the salutation of a formal letter, to separate hour from minute in a notation of time, and to separate the title of a work from its subtitle or a Bible chapter from a verse.