Complex sentence: Since August 1944, Szpilman was hiding out in an abandoned building at 223 Niepodległości Avenue when he was found in November by a German officer, Captain Wilm Hosenfeld.
Split into simpler sentences: Since August 1944, Szpilman was hiding out in an abandoned building at al. Niepodległości 223 when he was found in November by a German officer, Captain Wilm Hosenfeld.