I was wondering if someone could please help me confirm whether or not, after a relative pronoun preceded by a preposition, you can follow up with an infinitive immediately afterwards or if you have to construct a sentence segment featuring a fresh subject (and possibly auxiliary verb). Naturally, I have examples to clarify this query:
Is this possible:
This will be a good vantage point from which to rain fire down upon the enemy.
Or does it have to be phrased like this:
This will be a good vantage point, from which we can rain fire down upon the enemy?
The first of the two feels possibly correct, but I am not certain if it is strictly so.