Complex sentence: Daum began his football career in 1971 in the youth league with Hamborn 07, transferred in 1972 to Eintracht Duisburg and then in 1975 to 1.
Split into simpler sentences: Daum began his football career in 1971 in the youth league with Hamborn 07. He transferred in 1972 to Eintracht Duisburg and then in 1975 to 1.