1. I have begun to study Chinese.（我已经开始学习中文了。）2. They have begun to plan their summer vacation.（他们已经开始计划他们的暑假了。）2. They have begun to plan their summer vacation.（他们已经开始计划他们的暑假了。）2. The meeting has begun.（会议已经开始了。）总之，begun是一个常用的英语单词，表示“开始”或“着手做某事”，正确的发音是 /bɪˈɡʌn/。3. She has begun to write a book.（她已经开始写一本书了。）
