Punctuation

1. Use a comma in a compound sentence to separate two independent clauses linked by a coordinating conjunction (and, or, nor, but, so, for, or yet).

   INCORRECT	The mixture was prepared from the two premixes and the remaining ingredients were then combined.
   CORRECT	The mixture was prepared from the two premixes, and the remaining ingredients were then combined.

2. Use a comma to separate items in a series composed of three or more elements.

   The manager of spare parts is responsible for ordering, stocking, and disbursing all spare parts for the entire plant.

   Despite the presence of the conjunction and, most technical-communication style manuals require a comma after the second-to-last item. The comma clarifies the separation and prevents misreading.

   CONFUSING	The report will be distributed to Operations, Research and Development and Accounting.
   CLEAR	The report will be distributed to Operations, Research and Development, and Accounting.

3. Use a comma to separate introductory words, phrases, and clauses from the main clause of the sentence.

   However, we will have to calculate the effect of the wind.

   To facilitate trade, the government holds a yearly international conference.

   In the following example, the comma actually prevents misreading:

   Just as we finished eating, the rats discovered the treadmill.

   NOTE: Writers sometimes make errors by omitting commas following introductory words, phrases, or clauses. A comma is optional only if the introductory text is brief and cannot be misread.

   CORRECT	First, let’s take care of the introductions.
   CORRECT	First let’s take care of the introductions.
   INCORRECT	As the researchers sat down to eat the laboratory rats awakened.
   CORRECT	As the researchers sat down to eat, the laboratory rats awakened.

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4. Use a comma to separate a dependent clause from the main clause.

   Although most of the executive council saw nothing wrong with it, the advertising campaign was canceled.

   Most tablet computers use green technology, even though it is relatively expensive.

5. Use commas to separate nonrestrictive modifiers (parenthetical clarifications) from the rest of the sentence.

   Jones, the temporary chairman, called the meeting to order.

   For more about restrictive and nonrestrictive modifiers, see “Structuring Effective Sentences” in Ch. 6.

   NOTE: Writers sometimes introduce an error by dropping one of the commas around a nonrestrictive modifier.

   INCORRECT	The data line, which was installed two weeks ago had to be disconnected.
   CORRECT	The data line, which was installed two weeks ago, had to be disconnected.

6. Use a comma to separate interjections and transitional elements from the rest of the sentence.

   Yes, I admit that your findings are correct.

   Their plans, however, have great potential.

   NOTE: Writers sometimes introduce an error by dropping one of the commas around an interjection or a transitional element.

   INCORRECT	Our new statistician, however used to work for Konaire, Inc.
   CORRECT	Our new statistician, however, used to work for Konaire, Inc.

7. Use a comma to separate coordinate adjectives.

   For more about coordinate adjectives, see “Writing Grammatically Correct Sentences” in Ch. 6.

   The finished product was a sleek, comfortable cruiser.

   The heavy, awkward trains are still being used.

   The commas in these examples take the place of the conjunction and.

   If the adjectives are not coordinate—that is, if one of the adjectives modifies the combined adjective and noun—do not use a comma:

   They decided to go to the first general meeting.

8. Use a comma to signal that a word or phrase has been omitted from a sentence because it is implied.

   Smithers is in charge of the accounting; Harlen, the data management; Demarest, the publicity.

   The commas after Harlen and Demarest show that the phrase is in charge of has not been repeated.

9. Use a comma to separate a proper noun from the rest of the sentence in direct address.

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   John, have you seen the purchase order from United?

   What I’d like to know, Betty, is why we didn’t see this problem coming.

10. Use a comma to introduce most quotations.

    He asked, “What time were they expected?”

11. Use a comma to separate cities or towns, states, and countries.

    Bethlehem, Pennsylvania, is the home of Lehigh University.

    He attended Lehigh University in Bethlehem, Pennsylvania, and the University of California at Berkeley.

    Note that a comma precedes and follows Pennsylvania.

12. Use a comma to set off the year in a date.

    August 1, 2016, is the anticipated completion date.

    If the month separates the date and the year, you do not need to use commas because the numbers are not next to each other:

    The anticipated completion date is 1 August 2016.

13. Use a comma to clarify numbers.

    12,013,104

    NOTE: European practice is to reverse the use of commas and periods in writing numbers: periods separate hundreds and thousands, thousands and millions, and so on, while commas separate whole numbers from decimals.

    12.013,4

14. Use a comma to separate names from professional or academic titles.

    Harold Clayton, PhD

    Marion Fewick, CLU

    Joyce Carnone, PE

    The comma also follows the title in a sentence:

    Harold Clayton, PhD, is the featured speaker.

• Commas are not used to link two independent clauses without a coordinating conjunction (an error known as a comma splice).

• Commas are not used to separate the subject from the verb in a sentence.

• Commas are not used to separate the verb from its complement.

  INCORRECT	The schedules that have to be updated every month are, numbers 14, 16, 21, 22, 27, and 31.
  CORRECT	The schedules that have to be updated every month are numbers 14, 16, 21, 22, 27, and 31.

• Commas are not used with a restrictive modifier.

  INCORRECT	New and old employees, who use the processed order form, do not completely understand the basis of the system.
  	The phrase who use the processed order form is a restrictive modifier necessary to the meaning: it defines which employees do not understand the system.
  CORRECT	New and old employees who use the processed order form do not completely understand the basis of the system.
  INCORRECT	A company, that has grown so big, no longer finds an informal evaluation procedure effective.
  	The clause that has grown so big is a restrictive modifier.
  CORRECT	A company that has grown so big no longer finds an informal evaluation procedure effective.

• Commas are not used to separate two elements in a compound subject.

1. Use a semicolon to separate independent clauses not linked by a coordinating conjunction.

   The second edition of the handbook is more up-to-date; however, it is also more expensive.

2. Use a semicolon to separate items in a series that already contains commas.

   The members elected three officers: Jack Resnick, president; Carol Wayshum, vice president; Ahmed Jamoogian, recording secretary.

1. Use a colon to introduce a word, phrase, or clause that amplifies, illustrates, or explains a general statement.

   The project team lacked one crucial member: a project leader.

   Here is the client’s request: we are to provide the preliminary proposal by November 13.

   We found three substances in excessive quantities: potassium, cyanide, and asbestos.

   The week was productive: 14 projects were completed, and another dozen were initiated.

   NOTE: The text preceding a colon should be able to stand on its own as a sentence:

   INCORRECT	We found: potassium, cyanide, and asbestos.
   CORRECT	We found the following: potassium, cyanide, and asbestos.
   CORRECT	We found potassium, cyanide, and asbestos.

2. Use a colon to introduce items in a vertical list if the sense of the introductory text would be incomplete without the list.

   We found the following:

   • potassium

   • cyanide

   • asbestos

3. Use a colon to introduce long or formal quotations.

   The president began: “In the last year . . . .”

1. Use a period at the end of sentences that do not ask questions or express strong emotion.

   The lateral stress still needs to be calculated.

2. Use a period after some abbreviations.

   U.S.A.

   etc.

3. Use a period with decimal fractions.

   4.056

   $6.75

   75.6 percent

1. Use a dash to set off a sudden change in thought or tone.

   The committee found—can you believe this?—that the company bore full responsibility for the accident.

   That’s what she said—if I remember correctly.

2. Use a dash to emphasize a parenthetical element.

   The managers’ reports—all 10 of them—recommend production cutbacks for the coming year.

   Arlene Kregman—the first woman elected to the board of directors—is the next scheduled speaker.

3. Use a dash to set off an introductory series from its explanation.

   Wet suits, weight belts, tanks—everything will have to be shipped in.

   NOTE: When a series follows the general statement, a colon replaces the dash.

   Everything will have to be shipped in: wet suits, weight belts, and tanks.

1. Use parentheses to set off incidental information.

   Please call me (×3104) when you get the information.

   Galileo (1564–1642) is often considered the father of modern astronomy.

   The cure rate for lung cancer almost doubled in thirty years (Capron, 2016).

2. Use parentheses to enclose numbers and letters that label items listed in a sentence.

   To transfer a call within the office, (1) place the party on HOLD, (2) press TRANSFER, (3) press the extension number, and (4) hang up.

   Use both a left and a right parenthesis—not just a right parenthesis—in this situation.

1. Use an apostrophe to indicate possession.

   the manager’s goals	the employees’ credit union
   the workers’ lounge	Charles’s T square

   For joint possession, add an apostrophe and an s only to the last noun or proper noun:

   Watson and Crick’s discovery

   For separate possession, add an apostrophe and an s to each of the nouns or pronouns:

   Newton’s and Galileo’s theories

   NOTE: Do not add an apostrophe or an s to possessive pronouns: his, hers, its, ours, yours, theirs.

2. Use an apostrophe to indicate possession when a noun modifies a gerund.

   We were all looking forward to Bill’s joining the company.

   The gerund joining is modified by the proper noun Bill.

3. Use an apostrophe to form contractions.

   I’ve	shouldn’t
   can’t	it’s

   The apostrophe usually indicates an omitted letter or letters:

   can(no)t = can’t

   it (i)s = it’s

   NOTE: Some organizations discourage the use of contractions. Find out what the policy of your organization is.

4. Use an apostrophe to indicate special plurals.

   three 9’s

   two different JCL’s

   the why’s and how’s of the problem

1. Use quotation marks to indicate titles of short works, such as articles, essays, or chapters.

   Smith’s essay “Solar Heating Alternatives” was short but informative.

2. Use quotation marks to call attention to a word or phrase used in an unusual way or in an unusual context.

   A proposal is “wired” if the sponsoring agency has already decided who will be granted the contract.

   NOTE: Do not use quotation marks to excuse poor word choice:

   INCORRECT

   The new director has been a real “pain.”

3. Use quotation marks to indicate a direct quotation.

   “In the future,” he said, “check with me before authorizing any large purchases.”

   As Breyer wrote, “Morale is productivity.”

   NOTE: Quotation marks are not used with indirect quotations:

   INCORRECT	He said that “third-quarter profits will be up.”
   CORRECT	He said that third-quarter profits will be up.
   CORRECT	He said, “Third-quarter profits will be up.”

   Also note that quotation marks are not used with quotations that are longer than four lines; instead, set the quotation in block format. In a word-processed manuscript, a block quotation is usually introduced by a complete sentence followed by a colon and indented one-half inch from the left-hand margin.

   Different style manuals recommend variations on the basic rules; the following example illustrates APA style.

   McFarland (2011) writes:

   The extent to which organisms adapt to their environment is still being charted. Many animals, we have recently learned, respond to a dry winter with an automatic birth control chemical that limits the number of young to be born that spring. This prevents mass starvation among the species in that locale. (p. 49)

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   Hollins (2012) concurs. She writes, “Biological adaptation will be a major research area during the next decade” (p. 2).

• If the sentence contains a tag—a phrase identifying the speaker or writer—a comma separates it from the quotation:

  Wilson replied, “I’ll try to fly out there tomorrow.”

  “I’ll try to fly out there tomorrow,” Wilson replied.

  Informal and brief quotations require no punctuation before a quotation mark:

  She asked herself “Why?” several times a day.

• In the United States (unlike most other nations where English is spoken), commas and periods following quotations are placed within the quotation marks:

  The project engineer reported, “A new factor has been added.”

  “A new factor has been added,” the project engineer reported.

• Question marks, dashes, and exclamation points are placed inside quotation marks when they are part of the quoted material:

  He asked, “Did the shipment come in yet?”

• When question marks, dashes, and exclamation points apply to the whole sentence, they are placed outside the quotation marks:

  Did he say, “This is the limit”?

• When a punctuation mark appears inside a quotation mark at the end of a sentence, do not add another punctuation mark:

  INCORRECT	Did she say, “What time is it?”?
  CORRECT	Did she say, “What time is it?”

1. Use square brackets around words added to a quotation.

   As noted in the minutes of the meeting, “He [Pearson] spoke out against the proposal.”

   A better approach would be to shorten the quotation:

   The minutes of the meeting note that Pearson “spoke out against the proposal.”

2. Use square brackets to indicate parenthetical information within parentheses.

   (For further information, see Charles Houghton’s Civil Engineering Today [1997].)