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 verb.

Phrasal verbs represent a practically limitless group of verbs that can be combined with short adverbs or prepositions to produce new meanings. Here are some examples: Phrasal verbs are ubiquitous in ...

The preposition, ‘on’, features in a good number of phrasal verbs. A phrasal verb consists of a verb with a preposition or adverb (or both at times), with a meaning different from those of its ...