3.116 phrasal verbs in questions and relative clauses

There is one way in which a preposition that is part of a phrasal verb behaves differently from an ordinary preposition.

Normally, when the object of a preposition is put at the beginning of a question or a relative clause, it can be preceded by the preposition, especially in formal speech or writing. For example, you can say 'From which student did you get the book?' and 'the document on which he put his signature'.

However, if the preposition is part of a phrasal verb, it cannot be put before its object in such structures. You would have to say 'What are you getting at?' not 'At what are you getting?', and 'the difficulties which he ran up against' not 'the difficulties against which he ran up'.

• Who were they laughing at?
• This was one complication he had not bargained for.

3.117

Most phrasal verbs which contain a transitive verb can be used in the passive. So can a few phrasal verbs which consist of an intransitive verb, an adverb, and a preposition. See paragraphs 10.17 and 10.23.