I've seen a lot of sentences that finish in a preposition.
For example,
- She never took a taxi, even though she could afford to.
Why isn't this sentence like this?
- She never took a taxi, even though she could afford.
I've seen a lot of sentences that finish in a preposition.
For example,
Why isn't this sentence like this?
As @tchrist explains, the "to" there is not a preposition; instead, it's the first part of an infinitive verb phrase "to take a taxi," where the rest of the phrase is omitted.
But here's why the sentence (the one ending in "to") still makes sense. This is a case of verb-phrase ellipsis (see Wikipedia). This happens when part of a verb phrase is omitted because that part occurs elsewhere (usually earlier) in the text.
Another example of this would be the sentence: "you want to go to the store, but I don't." The rest of the verb phrase "don't want to go to the store" is omitted, because "want to go to the store" occurs earlier in the text and verb-phrase ellipsis is possible here.
Because the version you suggest isn't actually grammatical. It doesn't say what she could afford.
Believe it or not, it turns out that your original sentence does not end with a preposition! It ends with the infinitive-marking particle to, which is not a preposition here. That's because the verb afford to VERB takes a to-infinitive.
So the understood sentence when written out in full is really this one:
So that's what the original means. No preposition is involved.
If you want the afford by itself at then end, then you need it to be an afford NOUN type of thing, not an afford to VERB type of thing. For example:
But that takes more fiddling around, and there's no need for that.