A question mark is used to show the end of a question. Occasionally, a question mark is used to turn a sentence structured like statement into a question (e.g.,
A question mark is used to show the end of a question. Occasionally, a question mark is used to turn a sentence structured like statement into a question (e.g., 'You like this?') or with a question tag ('You like this, don't you?'). In Spanish, upside down question marks are used before questions.
Fired for Using Too Many Question Marks? It Really Happened. A Quick Guide to Punctuation Etiquette – The Visual Communication Guy
Question Marks Worksheets
Mastering Punctuation: The Difference Between Question Marks and Full Stops
Question mark games
Unlocking Answers: The Art of Interrogative Sentences - ESL Grammar
How to Use Question Marks (with Pictures) - wikiHow
Punctuation PDF, Language Resources
Question Mark Interesting Facts about Question Marks in English
Question Mark: Rules, Usage, and Examples - The Grammar Guide
The abuse of question marks — #67, by Jon Jackson, 100 Naked Words
eLimu Spelling and punctuation
Question Marks - Rules and Examples
Why is the question mark sometimes placed outside the quotes?
What is a question mark? - Quora