Stranding of the preposition
The preposition is often stranded at the end of a clause and is thus separated from its nominal complement. The alternative construction called ‘fronting’ keeps the preposition at the beginning of the clause, next to its complement.
Stranded preposition Fronted preposition
Which day are you referring to? (To which day are you referring?)
Do you know who this book belongs to? (Do you know to who(m) this book belongs?)
Bill is the kind of guy you’d be the kind of guy with whom
happy to have a drink with you’d be happy to have a drink) (formal)
Stranding is typical of spoken and informal written English, while the fronted counterparts are formal, and might be found in planned formal discourse.
When verb and preposition are tightly bound, the fronted alternative with a wh-interrogative may become so awkward as to be impossible. Not all combinations admit both versions, as for example be about, particularly if the subject (this) is not identified:
What’s this about? (What functions as the complement of about) About what is this?
(This version sounds awkward and strange, and would be avoided.
