Complex sentence: With the outbreak of the Second World War, she left for Vilna, then returned to Warsaw together with Chaikeh Grossman and was actively involved in the underground as a member of the Hashomer Hatzair combat unit.
Split into simpler sentences: With the outbreak of the Second World War, she left for Vilna, then returned to Warsaw and joined the underground. She was a member of the Hashomer Hatzair combat unit.