他打听火车时刻表只是一段纯粹的即兴曲。

His call for a book of the trains had been a sheer piece of impromptu.

第三部分论述了《即兴曲》的创作背景及重要地位；

The third part discusses the background and important role of impromptu.

八首即兴曲是舒伯特钢琴创作中较为重要的作品，集中体现了舒伯特独特的创作个性与风格。

Eight piano impromptus are very important in all Schubert 's piano works. They reflect Schubert' s composing style and individual character.