Answer: In this issue of "Q & A on Writing," I clarify the meanings of confusing words beginning with "P" and "Q": participle as possessive; prescribe/proscribe; preventive/preventative; principal/principle; prior to; prophecy/prophesy; protagonist/antagonist; punctuation with closing quotation marks.
With each item, I attach a "Scale of Distraction," a measure of how many readers are likely to be distracted by the mistake.
* Who cares?
** Some people you respect will be distracted by the mistake.
*** Many educated people will be distracted by the mistake.
Participle preceded by the possessive: an example will be the best explanation: "He was concerned about the plane's leaving." "Leaving" is a verbal noun, a participle. He was concerned about the "leaving," not the plane. "Plane" becomes possessive. If he were concerned about the plane, on the other hand, you would need to rewrite the sentence: "He was concerned about faulty maintenance on the plane, which was leaving." Got that?
"Prescribe" = to order; "proscribe" = to forbid.
Use "preventive," not "preventative." Why add an extra syllable?
"Principal" = head of school ("The principal is my pal") or mAin; "principLE" = ruLE. Thanks again to Harry Shefter's Six Minutes A Day to Perfect Spelling.
"Prior to....": Sounds pompous. Use "before."
"Prophecy" = noun; "prophesy" = verb.
"Protagonist" = central character in a drama; "antagonist" = adversary.
Quotes: remember that in America, periods and commas are ALWAYS placed INSIDE closing quotation marks. That includes single quotes. "According to her, everything was 'peachy clean.' "/ "Although she said everything was 'peachy clean,' the house was a mess."
Question marks and exclamation points are placed inside closing quotation marks if the entire sentence is a quote and outside the closing quotation marks if the quotation is only part of the sentence. "Are you going to stand there all day?"/She said she was going to stand there "all day if I have to"!
Semicolons and colons are ALWAYS placed OUTSIDE closing quotation marks.
All the best. RayS.