A答案：
Dear Tom:
How are you? I hope you are fine. Can you help me? I think my english is not very good. Need your help. Hope you will do that. A big thank to you!
Your friend
Ben
B答案：
Dear Tom:
You recently? I hope you are well. I recently met a little trouble, I hope you can help.
I think my English is not very good, so humbly ask you. I hope you can help me!
Send you thank. Also wish you happiness!
Your friend
C答案：
To Tom:
Hello friend. Do you have time to resolve some of my problem?
I think my English is not good like you, hope you can help me!
Thank you very much.
Your friend Ben.