[Ref. The McGraw-Hill Handbook of English Grammar and Usage]
A verb phrase is a phrase headed by a verb.
In the examples that follow, the verb head is in italics
and the verb phrase is underlined.
The well-dressed young woman glanced in the mirror.
The sleek new car in the driveway belongs to my grandmother.
Verb phrases must contain a "tensed" verb - either a present or past tense verb that agrees with the subjects of its clause. All verb phrases, in short, must exhibit subject-verb agreement.
Phrasal verbs contain a verb + preposition.
In the following sentence the phrasal verb is
Susan turned down the offer.
The key idea of phrasal verbs is that the verb plus
preposition compound acts as a single semantic
and grammatical unit. For example, we can
paraphrase the meaning of turned down with
the single verb rejected.
Susan rejected the offer.
The two sentences, Susan turned down the offer
and Susan rejected the offer, mean exactly
the same thing. The grammar of the two sentences
is also identical. In both cases, the noun phrase
the offer is the object of the verb.