A phrase is a group of words within a clause or sentence that go together as a unit or idea. The group of words go with a ‘head’ or ‘anchor’ word.

Noun phrases

In noun phrases, the head is the final noun or pronoun (e.g. a good job). It may be preceded by a determiner and up to 3 types of adjectives:

this/his                smart                    green                   Hawaiian           shirt
determiner         adjective              adjective              adjective            noun
                            [evaluative]          [descriptive]        [categorial]        [common]

See 'Commas and adjectives' in Common grammar questions for further explanation of types of adjectives and when to use commas in lists of adjectives.

Verb phrases

Verb phrases can consist of a simple verb, or a combination with other types (auxiliary and/or modal verbs). The lexical verb is always the one that expresses the action or process:

rolled                  was rolling                        could roll                     would have rolled          
lexical                 auxiliary + lexical             modal + lexical           modal + auxiliary + lexical

The simple verb makes the action either present or past tense, as does use of the auxiliary or modal verb at the start of the verb phrase. Modal verbs also show the writer’s orientation to the action: how sure or doubtful they are about it happening (e.g. will vs could).

Active and passive verb phrases

Active and passive verb phrases are both constructed with one (or more) auxiliary verb followed by a lexical verb:

  • The active verb phrase begins with the auxiliary has/had (verb to have) and ends with the past participle. 
  • The passive verb phrase begins with the auxiliary is/was (verb to be) and ends with the past participle.

Active:
They have announced it.     She has taken the book home. [have + past participle]

Passive:
It was announced.    The book is being taken home. [be + past participle]

Contracted verb phrases

When speaking, we often contract the auxiliaries or modals in verb phrases to make the utterance shorter. When the word not is embedded in the verb phrase, it is often contracted with the preceding auxiliary or modal verb:

I’m     he’s     she’s     it’s     we’re     you’re     they’re

I’ll     he’ll     she’ll     it’ll     we’ll     you’ll     they’ll

you’re [= you are]

you’re not   or   you aren’t [= you are not]

you’d [= you had/would]

you’d  not  or   you  hadn’t/wouldn’t [= you had/would not]    

See Apostrophes for information on other contracted words.

Prepositional phrases

A prepositional phrase is headed by a preposition and completed by a noun or noun phrase:

in bloom     in great haste     on the piano     under the radar     with a smile

They can be attached to a noun:   

See the jacarandas in bloom!     

It’s service with a smile.   

or attached to other prepositional phrases: 

They received letters from the family on the coast of New South Wales.

Prepositional phrases often serve as adverbial phrases or adjuncts to modify the verb: 

He left the room in great haste. [in great haste modifies left]

They put the flowers on the piano. [on the piano modifies put]

Prepositional phrases are very common in descriptive and expository writing.