Use of English PRO

One of the most (0) AMAZING advances ever made in medicine began with an (1) ............ (EXPECT) event. Sir Alexander Fleming had been looking into the (2) ............ (POSSIBLE) of finding a better way of killing germs when he came upon something (3) ............ (PUZZLE) in his laboratory. Some mould that had (4) ............ (ACCIDENT) landed on one of the dishes appeared to be killing the bacteria he was growing. At first, he was (5) ............ (EXCITE) about his (6) ............ (DISCOVER) and grew more of the mould, giving it the name of penicillin. However, in his view, it was only really (7) ............ (EFFECT) as an antiseptic against certain skin (8) ............ (INFECT) and soon lost interest. It wasn’t until ten years later that two other scientists managed to isolate the substance that killed the bacteria, and successfully began to save people’s lives with it.