Complex sentence: In 1992, the building changed further, the staff room was knocked through and made into two classrooms and enabled the corridor to run through the whole block, at the top end, the old girls school library provided a link to the new 1992 extension.
Split into simpler sentences: In 1992, the building changed further: the staff room was knocked through and made into two classrooms and enabled the corridor to run through the whole block. At the top end, the old girls school library provided a link to the new 1992 extension.