Complex sentence: In 1985, Abdullah attended the Armored Officer's Advanced Course at Fort Knox, and in 1986, he became commander of a tank company in the 91st Armored Brigade, holding the rank of Captain.
Split into simpler sentences: In 1985, Abdullah attended the Armored Officer's Advanced Course at Fort Knox. He became commander of a tank company in the 91st Armored Brigade, holding the rank of Captain.