Final answer:
Quotation marks can indicate sarcasm or irony and are crucial for correct punctuation when quoting. They help to avoid plagiarism and must be used with proper signal phrases and punctuation marks. Alterations to a quote require brackets or ellipses to show changes or omissions.
Step-by-step explanation:
Quotation marks are a type of punctuation that can be used to indicate sarcasm or irony. When presenting a quotation, it is crucial to use these punctuation marks correctly to maintain the intended meaning and provide clarity. For instance, colons and semicolons should be placed outside quotation marks, while question marks and exclamation points belong inside if they are part of the quoted material. Additionally, using quotation marks helps to avoid plagiarism by clearly demarcating where the quoted text begins and ends. Signal phrases are equally important and should be complemented with commas to integrate the quotation properly into your sentence structure. When changes are necessary to fit the quote within your writing, brackets and ellipses are the appropriate tools to signal alterations or omissions without distorting the original message.