谁？时间？ 什么事情？ 要求？

范文：

Apr. 20，2008

Dear Yang,

        A Mr. Liu Bing called you this morning but you were not in. He wanted to meet you this coming Saturday, 9 a.m., at the university gate. If that is not convenient for you, you are requested to ring him up at any time evening from 8 p.m. to 10 p.m. at 123454576.Yours,AmeliaApr. 20，2008Dear Fiona,This afternoon, I came to your dormitory to return” Gone with the Wind” that you had kindly lent me last week. Unfortunately, you were not here and your roommates seemed to be out as well. I had no choice but to take the book back. I wonder if you could contract with me anytime in the evening so that I could find appropriate time to visit you.

                                                                                                                                                           Sincerely yours,

                                                                                                                                                                     Amelia