Serial comma toast. Adding a serial comma removes this ambiguity. Writers who normally avoid the serial comma often use one in these circumstances, although sometimes re-ordering the elements of such a list can help as well. In some circumstances using the serial comma can create ambiguity. If the book dedication above is changed to the serial comma after "Ayn Rand" creates ambiguity about the writer's mother because it uses punctuation identical to that used for an appositive phrase, leaving it unclear whether this is a list of three entities (1, my mother; 2, Ayn Rand; and 3, God) or of only two
Punctuation of English their cover letters. In contrast, closed punctuation uses commas and periods in a strict manner. Closed style is common in presentations, especially in bulleted and numbered lists. It is also frequently used in advertising, marketing materials, news headlines, and signage. The approximate average frequencies for English punctuation marks per 1000 words based on 723,000 words of assorted texts are as follows (as of 2013, but with some text corpora dating to 1998 and 1987): The apostrophe , (sometimes called inverted comma in British English) is used to mark possession as in ""John's book"", and to mark letters omitted in contractions,