Particles Versus Prepositions

Phrasal verbs are very different from verbs with prepositions semantically and syntactically. In phrasal verbs the particle is intrinsically connected to the verb to form a single semantic unit. With verbs followed by prepositions, the preposition is part of a prepositional phrase and does not change the meaning of the verb.

Phrasal Verb: Max looked up Mary's number.
Verb + Preposition: Max looked up the corridor.

The phrasal verb, look up means to search for something in a reference work. In the verb followed by preposition, version, the preposition up does not change the meaning or sense of the verb look, to employ one’s sight or vision.

The particle in the phrasal verbs in this case can move in ways that prepositions in verbs followed by prepositions cannot.

Max looked Mary's number up.
*Max looked the corridor up. (INCORRECT)

Also notice that when we front a prepositional phrase, the only meaning or sense we can derive is that of the non-phrasal verb.

Max looked up the corridor?
Max looked up what?
Up What did Max look?
Max looked up Mary's number.
Max looked up what?
*Up what did Max look?(INCORRECT)(only grammatical with verb + prep. meaning)

In the case of verbs followed by prepositions, we can conjoin prepositional phrases. Whereas with the phrasal verbs, we cannot conjoin prepositional phrases to them.

Max looked up the corridor and down the hallway.
*Max looked up Mary's number and down the hallway (INCORRECT)