请用英文回答：What documents are often enclosed in business letters?
举一反三
- 请用英文回答：Why should business letters be marked Reference？
- 请用英文回答： What are the components of the business letter structure？
- 请用英文回答：Should postscript be written often？
- 请用英文回答：How to make a business letter courteous?
- Notices, letters, memos, and reports are the most fundamental business documents in business writing.