In conversation, it's normal to say:

What time do you have to be at the train station by?

Note: What time do you have to be at the train station vs What time do you have to be at the train station by, mean 2 completely different things, right?

1) The question in the title

2) Whether by is a preposition or not.

Winston Churchill once said

"That is the sort of thing up with which I will not put!

  • I'm arguing against duplicate as I'm talking about specific examples. Also the duplicate does not answer Q2.
    – Chris
    Jun 1 '18 at 15:24
  • @Chris The fact that you’re talking about specific examples doesn’t really change much. The example you give is subject to the same rules of preposition stranding as all other sentences. The second of your questions can be answered easily just by looking up the word by in the sense you have here (ODO has it as sense 4)). Jun 1 '18 at 15:52
  • The duplicate's answers did not go into detail on why prepositions are used at the end of sentences, simply stating "it's common" or "it's okay"; even the detailed answers could of not answered my question as good as KarlG did.
    – Chris
    Jun 1 '18 at 15:54

In informal registers, when a wh-interrogative pronoun is the object of a preposition, it is common for the preposition to shift to clause-final position:

What book are you interested in?
Who are you baking a cake for?
What school do her children go to?
Who did he come to the dance with?

If a “heavier” sentence element like a prepositional phrase intervenes, one can also hear:

Who did he come with to the spring dance?

In more formal registers, stranded prepositions such as these might be considered out of place, but simply slapping the preposition in front of the interrogative can yield an awkward sentence:

In what book are you interested?
What book interests you?
What book are you interested in reading?

To what school do her children go?
What school do her children attend?
Where do her children go to school?

Beginning a question with with or for whom will not, in formal registers, cause odd stares.

According to the source cited above:

With which card did you pay?

is just as acceptable in formal registers as informal.

Grammar is not absolute, but contextual. In informal settings, no one but the most dessicated pedant would insist the stranded preposition in these questions is a grammatical error.

The difference in meaning between your example sentences is minimal. By has the air of the future perfect about it: “By what time will you need to have arrived at the station to catch your train?” Just asking what time you need to get to the station asks only for a single point of arrival. In any case, the answer is going to be the same.

By, by the way, is a preposition whose object is the what-phrase.

The supposed Churchill quote ridiculing a narrow hyperprescriptivism is purported to have originally read:

This is the sort of bloody nonsense up with which I will not put.

This sounds a lot more like Churchill, but, alas, the chances of the statesman ever having actually uttered the sentence seem rather slim.

  • 1
    Minor niggle: when the preposition appears at the end, it is because it has not shifted, but remains in its underlying position (before the object trace). I’d also consider “With which card did you pay?” highly stilted and quite unusual in informal registers—but yes, perfectly grammatical. Apart from that, good answer. Jun 1 '18 at 15:46
  • I'm reminded of With what shall I fix it, dear Liza, dear Liza? With what shall I fix it, dear Liza, with what?, which even as a child always struck me as "awkward" syntax (long before I even knew the word "syntax"). I see from that Wikipedia article that the "original" was German, so maybe that's a factor in the "quirky" word sequence (or maybe it's just a matter of meter / rhythm, which obviously matters quite a bit for a children's song). I think it's not "informal" at all - it's positively "starchy". Jun 1 '18 at 16:20
  • 1
    When Dad would put young Mary to bed in the evening, he would read her a story from a book before he turned out the light and left the room. Mary liked Grimm's fairy tales, but Hans Andersen's not so much, so one evening, when Dad started to read her "The Little Mermaid", she complained, "Daddy, what did you bring that book I didn't want to be read to out of up for?"
    – tautophile
    Jun 1 '18 at 17:56

Not the answer you're looking for? Browse other questions tagged or ask your own question.