11. English Language Punctuation - Period The period is a mark of separation. Its primary purpose is to separate complete thoughts, to mark the end of declarative and imperative sentences. (Interrogative sentences end with a question mark; exclamatory, with an exclamation point.) The key word here is complete; a period should be used only after a sentence complete with subject and predicate. Do not use a period after headings on separate lines (run-in headings are often separated from text by a period), after running heads, after table titles, or after items in an enumerated, displayed list unless one or more of the items are complete sentences: The purposes of this report are 1. English Language Punctuation - 2. English Language Punctuation - To evaluate the performance of instruments To expand the data base We can define the requirements of the power converter as follows: 1. English Language Punctuation - 2. English Language Punctuation - .Energy conversion should be high. Efficiency should be independent of laser wavelength. It is customary to end figure captions with a period whether or not they are complete sentences: Figure 1. English Language Punctuation - Computing scheme for algorithm. Figure 1. English Language Punctuation - Concluded. 11. a) English Language Punctuation - Abbreviations A period may follow abbreviations except those for units of measure. The trend is away from periods for abbreviations (Skillin et al. 1974; and Chicago Press 1982), but they are retained for many word abbreviations, particularly those that may be confused with an unabbreviated word: fig. 1 Co. no. 209 Mr. Periods are not used for abbreviations of units of measure (except inch), for acronyms, or for contractions (with apostrophe): ft NASA cm V/STOL lb nat'l A period does follow the abbreviation for inch 1 in. 14 lb/in. but in/hr in-lb, 6-in-wide Whether or not to end an abbreviation with a period is best determined by consulting G.P.O. Style Manual Webster's Collegiate or Unabridged Dictionary 11. b) English Language Punctuation - Conventional Uses of the Period The period is so useful for separation that several conventional uses exist.
