Question mark
In the early 13th century, when the growth of communities of scholars (universities) in Paris and other major cities led to an expansion and streamlining of the book-production trade, punctuation was rationalized by assigning Alcuin's stroke-over-dot specifically to interrogatives; by this time the stroke was more sharply curved and can easily be recognized as the modern question mark.
Question mark
In English, the question mark typically occurs at the end of a sentence, where it replaces the full stop (period). However, the question mark may also occur at the end of a clause or phrase, where it replaces the comma :