给下列人写信应如何开头：你的姐姐，你的朋友比尔，你的老板，你的老校长。

How would you begin a letter to: your sister, your friend Bill, your employer, your old headmaster?

给下列人写信时你如何开头：你的表弟特德，你的银行经理，你的朋友玛丽，你的祖父？

How would you begin letters to: your cousin Ted, your bank manager, your friend Mary, your grandfather?