Priority Among Punctuation Marks

As I hope you have gathered by now, punctuation marks are, in most cases, independent of one another. Each mark is inserted to do a particular job, and using one mark neither allows you to drop another one which is independently required nor permits you to insert one or two extra marks which are not needed. There are, however, a few exceptions.

First of all, we never write two full stops at the end of a sentence. Observe the following examples:

Officially, the clocks will go back at 2.00 a.m.
Leo Durocher never in fact made that famous remark "Nice guys finish last."

The abbreviation and the direct quotation already end in full stops, so no second full stop is written. Similarly, if a sentence would logically end in two question marks, only the first is written:

Who wrote the sonnet that begins "How do I love thee?"

If a sentence-final quotation ends in a question mark or an exclamation mark, no full stop follows:

Pontius Pilate famously asked "What is truth?"

However, a question mark is written after a full stop if this is logically required:

Does the flight arrive at 7.00 a.m. or 7.00 p.m.?

You already know that the second of two bracketing commas or dashes is not written at the end of a sentence. This is because the comma or dash that would logically appear there is "outranked" by the full stop or other mark that appears at the end of the sentence:

The Spaniards and the Canadians are close to war over fishing rights, it would appear.
We commonly assume that there are only two sexes — but could we be wrong?

In the same way, a comma that should logically appear is suppressed if a colon or a semicolon is present at the same position:

The planet Venus is a hellhole, as the Russian probes have revealed; no human could survive for a moment on its surface.
Only two groups are excluded from the French Foreign Legion, according to the rules: women and Frenchmen.

In these examples the second bracketing commas that would logically appear after the words revealed and rules are suppressed by the following colon and semicolon. Here is a useful rule of thumb: a comma is never preceded or followed by any other punctuation mark at all, except possibly by a quotation mark or by a full stop which forms part of an abbreviation.

Copyright © Larry Trask, 1997

Maintained by the Department of Informatics, University of Sussex