Complex sentence: In 1915 he became an apprentice mechanical turner in Lisbon, four years later, in 1919 he started doing the same work in the Arsenal of the Portuguese navy in Alfeite.
Split into simpler sentences: In 1915 he became an apprentice mechanical turner in Lisbon. Four years later, in 1919 he started doing the same work in the arsenal of the Portuguese navy in Alfeite.