Complex sentence: A blue-collar work experience was a pre-requisite for admission into the university; after a year of work Sokolov was allowed to enroll at the Department of Geology and Soil Sciences of the Leningrad University.
Split into simpler sentences: A blue-collar work experience was a prerequisite for admission into the university. After a year of work Sokolov was allowed to enroll at the Department of Geology and Soil Sciences of Leningrad University.