Some verbs are followed by adverb particles. Examples are: put on, take off, give away, bring up, call in.
He was brought up by his grandmother.
Sometimes the particle is detached from the verb and put after the object.
He took his boots off.
They called the doctor in.
John put his hat on.
He threw the apple away.
You must send them back.
Note that the particle is put after the object, when the object is a personal pronoun – it, me, us, them etc. – or when it is comparatively short.
Many words can be used as both adverb particles and prepositions. There is some difference between an adverb particle and a preposition. While the particle is closely tied to its verb to form idiomatic expressions, the preposition is closely tied to the noun or pronoun it modifies.
The following words are used only as particles and never as prepositions – away, back, out, backward, forward, upward, downward.
When the object is long or has to be made prominent or when it is qualified by an adjectival phrase or clause, the particle comes before the object.
The principal gave away the prizes.
He put on an air of innocence.
He brushed aside all the plans I had carefully formulated.
The sailors put out the fire in the hold of the ship.
We should not throw away anything useful.