Complex sentence: In 1900--1901 he is drafted and must interrupt his studies; after his military service he returns to Budapest, passes the fundamental examination in 1902; in 1904 he passes the specialty examination and obtains the Diploma of professor for higher commercial schools.
Split into simpler sentences: In 1900--1901 he is drafted and must interrupt his studies. After his military service he returns to Budapest, passes the fundamental examination in 1902; in 1904 he passes the specialty examination and obtains the Diploma of professor for higher commercial schools.