Complex sentence: From 1984 to 1986, Kvachkov served in Pskov, from 1986 to 1989 he was the Chief of the Staff of a brigade in the Group of Soviet Forces in Germany.
Split into simpler sentences: From 1984 to 1986, Kvachkov served in Pskov. From 1986 to 1989 he was the Chief of the Staff of a brigade in the Group of Soviet Forces in Germany.