例5.Discoveries in science and technology arethought by"untaught minds"to come in blinding flashesor as the result of dramatic accidents.Sir AlexanderFlening did not,as legend would have it,look at themold(霉)on a piece of cheese and get the idea for peni-cillin there and then.He experimented with antibacterialsubstances for nine years before he made his discovery.Inventions and innovation almost always come out of la-borious trial and error.Innovation is like soccer;eventhe best players miss the goal and have their shotsblocked much more frequendy than they score.