Pattern match is a very powerful resource, saving time and also allowing for some introspective journey into the structure of language, something that being busy all the time (with grading open questions for example...) is becoming increasingly rare. So thanks for giving us this possibility at the same time!,
However there is a potential risk in case the question is of the type "give a definition of.....[anything]" as it is possible, and very quick too, to open a wikipedia page, look for the wanted definition and paste it into the answer field. Many wikipedia pages start with short definitions, very often within the limit of 20 words suggested by the PM syntax help, and they inevitably match the pattern set in the question rules. This can be worked around with formative quizzes (e.g interactive with multiple tries) where the feedback could state the wikipedia origin and the quiz ask for editing the answer, but in case of summative quizzes with deferred feedback I couldn't find a way to obtain the same (state the wikipedia origin + ask and allow for an editing), and in principle anyone with appropriate knowledge could generate the same sentence as found in wikipedia. Anyone experiencing the same problem or having already solved this issue?