From zmjezhd's link above:

Quote:
(2a) That tiny hole is the place which the mouse escaped from.
(2b) That tiny hole is the place from which the mouse escaped.
(2c) That tiny hole is the place wherefrom the mouse escaped.


(3a) My car was broken into last night.

(3b) Somebody broke into my car last night.


In (2a), if you're into which-hunting, since the phrase 'the mouse escaped from' is restrictive, it should be introduced by that, not which. This means that after moving the preposition forward to where it allegedly belongs, you would have the sentence
Quote:
(2b) That tiny hole is the place from that the mouse escaped.


In the case of the sentences (3a) and (3b) I would suggest that the word into is not a preposition but the particle of a phrasal verb. In this case it is not one that can be put at the end of a sentence. We have

(3a) My car was broken into last night.

but not

*(3c) My car was broken last night into.

This is unlike the pair

(4a) Jack and Jill ran up a big bill.

(4b) Jack and Jill ran a big bill up.

In this case up is not a preposition but the particle of a phrasal verb, one that can be moved to the end of the sentence.

As for the split infinitives it is not difficult to find examples where the so-called rule leaves us with sentences that cannot be expressed properly without splitting the infinitive. The sentence will either say something that is not meant or will be hopelessly clunky.