Periods (.) are placed at the end of a fact or an opinion sentence
Use a question mark (?) to indicate a direct question when placed at the end of a sentence.
The exclamation point (!) is used when a person wants to express outcry or add emphasis.
More than one punctuation at the end of a sentence
If there is more than one punctuation at the end of the sentence, do not use a period.
Punctuation and Parentheses
Punctuation goes on the outside of the closing parenthesis.
If the entire sentence is in the parentheses, the punctuation goes inside. This is rare in academic writing.
Quotation Marks and Punctuation
With quotation marks, the period goes on the inside of the quotes
If there's a different punctuation mark on the inside of the quotes, do not add a period.
Apostrophes (') are used in contractions (words made by shortening and combining two words)
*Some instructors may prefer no contractions in research papers.
Apostrophes are used to indicate possession or ownership
For singular nouns add apostrophe and s ('s).
For plural nouns that end in s just add the apostrophe ( ' )
When a noun ends in an "us" or "eez" sound
It's and Its
It's is a contraction of it and is.
Its is a possessive form of it.
Quotation marks (" ") are a pair of punctuation marks mostly used to mark the beginning and end of a phrase that someone else has said. Periods and commas go within quotation marks. Place all other punctuation marks (colons, semicolons, exclamation marks, question marks) outside the quotation marks, except when they were part of the original quotation.
Single quotation marks (' ') are used most frequently for quotes within quotes.