Complex sentence: After graduating from high school in Varna, he worked as a teacher in Nikopol from 1895 to 1897, where he joined the Bulgarian Workers' Social Democratic Party (BWSDP).
Split into simpler sentences: After graduating from high school in Varna, he worked as a teacher in Nikopol from 1895 to 1897. In 1897, Kolarov joined the Bulgarian Workers' Social Democratic Party (BWSDP).