这本书的序言详细介绍了作者的研究方法和目的。

The ___preface of this book outlines the author's research methods and objectives in detail.

作者在序言中简要介绍了本书的创作背景。

The author included a short ___preface explaining the background of this book.

她在演讲前先简短地介绍了活动的背景。

She ___prefaced her speech with a brief introduction about the event's background.