This letter is to explain bad or unexpected grades.
1234, Main Street
Boston, MA 02123
09 April, 2005
<Recipient Address Goes Here>
You've probably seen my report card by now, and since I haven't been picked up by any large hairy men and dumped into the nearest body of water, I guess you've calmed down. So I'd like to explain each grade in detail, in the hopes that you'll understand. First off, my <first class> grade happened because the teacher hates my hair. Really. The <grade> in <second bad class> was because I had all my work for the final paper on a floppy disk and it fell in the storm drain. <explanation of further bad grades>. Are we clear now? I hope you can overlook these incidents (I'm doing my best to forget them, I assure you) and we can move on. Thanks for your patience and tuition.
encl: <List of enclosed items goes here>