<P>This is a letter (&nbsp;&nbsp;&nbsp;&nbsp; ) my father.</P>
<P>&nbsp;这里应该用to 还是for?</P>

to
that's ok

应该用for

write a letter to my father .&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; This is a letter for my father

同意楼上的观点for

我也认为是for 但有的老师说应该用to
郁闷中

for表示你所做动作的目的，例如：You bought the book for me .而to 则表示你动作的接受者，例如：You gave the book to me .

用to,有一种传递的意思

谁能给我最终下个结论

应该用for