A {horrible|dreadful|terrible} thought {struck|hit|occurred to} Harry, as {horrible|dreadful|terrible} thoughts always do when you're {very|extremely|incredibly} nervous. What if he wasn't chosen at all? What if he just sat there with the hat over his eyes for ages, until Professor McGonagall jerked it off his head and said there had obviously been a mistake and he'd better get back on the train?
A {horrible|dreadful|terrible|frightening} thought {struck|hit|occurred to|came to} Harry, as {horrible|dreadful|terrible|frightening} thoughts always do when you're {very|extremely|incredibly} nervous. What if he wasn't {chosen|selected|picked} at all? What if he just sat there with the hat over his eyes for {ages|a long time|what seemed like forever}, until Professor McGonagall jerked it off his head and said there had obviously been a mistake and he'd better get back on the train?