Complex sentence: Legislatures plan their business within a legislative calendar, which lays out how Bills will proceed before a session ceases, though related, but unofficial, affairs may be conducted by legislators outside a session or during a session on days in which parliament is not meeting.
Split into simpler sentences: Legislatures plan their business within a legislative calendar, which lays out how Bills will proceed before a session ceases. Nevertheless, some related, but unofficial, affairs may be conducted by legislators outside a session or during a session on days in which parliament is not meeting.