Mark each phrase below with O (Opening remark) or C (Closing remark)

1. I hope you find my advice...
   [O|C]
2. Thank you for your letter...
   [O|C]
3. Thanks for writing about...
   [O|C]
4. Remember/Don't forget that...
   [O|C]
5. Let me know how/about...
   [O|C]
6. I was sorry to hear that...
   [O|C]