Page 467 - Practical English Usage 3ed - Michael Swan, Oxford

prepositions (5): at the ends of clauses 452
She's the only woman (who) I've ever really been in love with.
That's what I'm afraid of.
Because whom is unusual in an informal style, it is very rare in clauses that end with prepositions (see 498.3,7).
4 passives
In passive structures (see 412-420), prepositions go with their verbs.
She likes to be looked at.
I don't know where he is - his bed hasn't been slept in. Carol was operated on last night.
S infinitive structures
Infinitive complements (see 284-285) can have prepositions with them. The village is pleasant to live in.
She needs other children to play with. Can you get me a chair to stand on? I've got lots ofmusic to listen to. Their house isn't easy to get to.
6 exceptions
7
Many common adverbial expressions consist of preposition + noun phrase (e.g. with great patience, in a temper). In these cases, the preposition is closely connected with the noun, and is kept as near as possible to it; it cannot usually be moved to the end of a clause.
Iadmiredthepatiencewithwhichshespoke. (NOT ••• thepttfienceshesp6ke tt!ith:)
Duriflg and since are not normally put at the ends of clauses.
During which period did it happen? (NOT Which peritJd tlid it ha1'1'en
tlttri,zg?>
Since when have you been working for her? (NOT :W'hen MtJe ytJtt been
WtJrking for her since?)
formal structures
In a more formal style, a preposition is often put earlier in questions and relative structures. before the question word or relative pronoun.
With whom did she go?
It was the house about which he had told them.
She was the only woman with whom he had ever been in love.
This can also happen in infinitive complements, in a very formal style. A relative pronoun is used.
She needs other children with whom to play.
It is a boring place in which to live.
Note that after prepositions which and whom can be used. but not normally who and that.
Even in a very formal style, prepositions are not often put at the beginning of questions which have be as the main verb.
Who is itfor, madam? (NOT ~iHt1)
And the structures where. . . to. what . .. like and what . .. for have a fixed order.
Where shall I send it to? (BUT NOT T8 where a.'taU : seltti it?) .. page 435