Complex sentence: Every day of the week is 25-hours long except for Thursday (How long it is now is unknown), and the change in the length of the year led to the creation of new months such as Janril, Febtober, and Marchuary.
Split into simpler sentences: Every day of the week is 25-hours long, except for Thursday (the length of which is unknown). The change in the length of the year led to the creation of new months such as Janril, Febtober, and Marchuary.