Grammatically Correct: The writer's essential guide to punctuation ...

GRAMMAR
Overdoing this type of sentence construction can make writing
look clumsy or unsubtle, however, so use it with discretion. If there
is an alternative wording that would allow your points to come
through just as clearly and elegantly, you should go with it instead.
But do not avoid putting a conjunction up front simply out of
principle.
ENDING A SENTENCE WITH A PREPOSITION
Prepositions are the words that define the relationships between
other words: Please put the skeleton in the closet; I'll meet you at
the drugstore after the concert; we went across the country; she
liked her salad with hot sauce on it. Many prepositions have to do
with time, space or position.
A persistent myth is that a preposition may never come at the
end of a sentence. For example, many students are taught that
sentences such as It's a subject I haven't thought about and You
have to remember where he's coming from should be worded as
It's a subject about which I haven't thought and You have to
remember from where he's coming. Again, the origins of this custom
lie in Latin, in which a preposition cannot come after its target
word. In English, however, the effect of ordering words this way is
often to turn a phrasing that sounds natural and spontaneous into
something tortured.
As with splitting infinitives, you may, as a general rule, prefer to
avoid ending sentences in prepositions simply because of your
readers' expectations. And indeed, sentences that follow the stricture
sometimes do sound more elegant. For example:
There are a couple of issues I'm willing to be more flexible on.
REVISED: There are a couple of issues on which I'm willing to be more
flexible.
It's astonishing that there are people this news comes as a surprise to.
REVISED: It's astonishing that there are people to whom this news comes
as a surprise.
There are some questions there are no easy answers for.
REVISED: There are some questions for which there are no easy answers.
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