reference synchronizing amplifier

例句：

1. 1.The book is a good reference for those who want to learn English.
   这本书是那些想要学习英语的人的好参考。
2. 2. She referred to the document as her final reference.
   她把那份文件当作她的最终参考资料。
3. 3.He referred to his experience as a reference for new employees.
   他将他的工作经验作为新员工的参考资料。