请用英文回答：In Middle Paragraph, what necessary background and supporting information should be beprovided?
举一反三
- 请用英文回答：What are the contents of Last Paragraph?
- what information should a poster include?一份海报一般包括几方面的要素？（请用英文回答））
- 请用英文回答：What are the principles of writing Opening Paragraph？
- 请用英文回答：What should the writer do if he want to achieve clarity ?
- Is the background information necessary in the introduction of narration?