consider these two sentences:
- 'He broke down on the Dover to Canterbury Road.'
- 'I was too close to the car in front so I dropped back.'
In these examples, down and back are not prepositions
but function as adverbs to extend or change the meaning of the verb.
This combination of verb and adverb is always known as a phrasal
that it is not always possible to guess the meaning of phrasal verbs
(or prepositional verbs for that matter) from the normal meaning
of the verb. Instead, you may need to try to guess the meaning from
the context, or, failing that, you might have to look it up in a