based on 3C ex.5
Read the text and choose the correct answer.

Sir Alexander Fleming was born in Scotland in 1881. He [was attending|had attended|had been attending] three different schools before he [moved|had moved|was moving] to London to study at Regent Street Polytechnic. He [worked|had been working|had worked] at a shipping office for four years when, in 1901, he left his job and went to St. Mary's Hospital, where he [had studied|was studying|studied] medicine. During World War I, Dr. Fleming [had served|served|was serving] as a doctor in the Royal Army. There he saw many soldiers dying from infections. Fleming felt that there had to be something that could kill bacteria without causing harm to the human body. For many years he [searched|had been searching|was searching] for an effective antiseptic, but it [wasn't|hadn't been|wasn't being] until 1928 that he discovered penicillin. Fleming continued his work until his death in 1955. By the time of his death, Alexander Fleming [was winning|had been winning|had won] many important awards, including the Nobel Prize in Medicine.