A notice with one exceptional closure

An original Czech notice reads: “Knihovna je otevřena od pondělí do pátku od devíti do osmnácti hodin. První pondělí v měsíci je zavřeno. V sobotu je otevřena jen dopoledne”. A learner says the library is open every Monday because the ordinary schedule begins with Monday. Another assumes that Sunday has the same hours as Saturday, although the notice says nothing about Sunday. The task asks learners to identify the exceptional closure and the limits of the information. No real library, holiday timetable or registration rule is supplied. This is an original classroom exercise rather than a quotation from an actual institution. The response should connect the ordinary schedule, exception and limiting word jen instead of choosing the option that repeats the most familiar day.