I know the rule:
I wrote them a letter
I wrote a letter to him.
But what about these sentences:
- How often do you write to/__ your parents.
- She is going to write __ / to me in a week.
My gut feeling is that it must be ‘write to your partents’ (with ‘to’ in the first sentence and without ‘to’ in the other. Please prove me right or wrong and explain me why ‘to’ must or must not be used in the examples above.