1 Each phrase plays a part in the clause or sentence. Here are some examples.
_____________________________________________________________
Subject              Verb               Adverbial
_____________________________________________________________
The flight            is leaving         shortty.
_____________________________________________________________
Subject              Verb               Complement
_____________________________________________________________
The weather       is                     very good.
My father           was                 a pilot.
_____________________________________________________________
Subject              Verb               Object
_____________________________________________________________
I                         was reading    a newspaper.
Two stewards    served             lunch.
_____________________________________________________________
Subject              Verb               Object               Adverbial
_____________________________________________________________
The aircraft        left                   London             at three o'clock
We                    must book       the tickets          next week.
_____________________________________________________________

2 These are the elements of an English sentence and the kinds of phrase that we can
use for each element.
Subject              Noun phrase: the flight, I, two stewards
Verb                  Verb phrase: is, served, must book
Object               Noun phrase: a newspaper, lunch
Complement     Adjective phrase: very good
                         Noun phrase: a pilot
Adverbial           Adverb phrase: shortly
                         Prepositional phrase: at three o'clock
                         Noun phrase: next week
NOTE
  a The verb is central to the sentence and we use the word 'verb' for both the sentence
     element - 'The verb follows the subject' - and for the word class - 'Leave is a verb.'
     For more details about sentence patterns. > 7
  b The word three can be the subject. > 50
        There was a letter for you.

There are fiive kinds of phrase.

1 Verb phrase: come, had thought, was left, will be climbing
   A verb phrase has an ordinary verb (come, thought, left, climbing) and many also
   have an auxiliary (had, was, will).

2 Noun phrase: a good flight, his crew, we
   A noun phrase has a noun (flight), which usually has a determiner (a) and/or
   adjective (good) in front of it. A noun phrase can also be a pronoun (we).

3 Adjective phrase: pleasent, very late
   An adjective phrase has a adjective, sometimes with an adverb of degree (very).

4 Adverb phrase: quickly, almost certainly
   An adverb phrase has an adverb, sometimes with an adverb of degree (almost).

5 Prepositional phrase: after lunch, on the aircraft
   A prepositional phrase is a preposition + noun phrase.

1 There are different classes of word, somtimes called 'parts of speech'. The word
come is a verb, letter is a noun and great is an adjective.
NOTE
  Some words belong to more than one word class, For example, test can be a noun or a verb.
     He passed the test. (noun)
     He had to test the machine. (verb)

2 There are eight main word classes in English.
Verb:                 climb, eat, welcome, be
Noun:                aircraft, country, lady, hour
Adjective:          good, British, cold, quick
Adverb:             quickly, always, approximately
Preposition:        to, of, at, on
Determiner:        the, his, some, forty-five
Pronoun:            we, you, them, myself
Conjunction:      and, but, so
NOTE There is also a small class of words called 'Interjection'. They include oh, ah and mhm.

3 Verbs, nouns, adjectives and adverbs are 'vocabulary words'. Learning vocabulary
means learning werbs, nouns, adjectives and adverbs.

Prepositions, determiners, pronouns and conjunctions belong to much smaller
classes. There words are sometimes called 'grammatical words'.

4 Most word classes can be divided into sub-classes. For example:
Verb                  Ordinary verb: go, like, think, apply
                          Auxiliary verb: is, had, can, must
Adverb              Adverb of manner: suddenly, quickly
                          Adverb of frequency: always, often
                          Adverb of place: there, nearby
                          Linking adverb: too, also
                          etc.
Determiner         Article: a, the
                          Possessive: my, his
                          Demonstrative: this, that
                          Quantifier: all, three

A FLIGHT ANNOUNCEMENT

'Good evening, ladies and gentlemen. On behalf of British Island Airways, Captain Massey and his crew welcome you on board the start Herald Flight to Southampton. Our fight time will be approximately forty-five minutes, and we shall be climbing to an altiude of eight thousand feet and cruising at a speed of two hundred and fifty miles per hour.'
(from M. Underwood and P. Barr Listeners)

The grammatical unit of English are words, phrase, clauses and sentences.

1 Words
The words in the announcement are good, eveing, ladies, and gentlemen, on etc.
NOTE For word-building, e.g. air + ways = airways, > 282

2 Phrase and clauses
We use phrases to build a clause. Here is an example.
___________________________________________________________________________
Subject                        Verb                       Complement
(noun phrase)              (verb phrasse)       (noun phrase)
___________________________________________________________________________
Our flight time              will be                     approxiamately forty-five minutes.
___________________________________________________________________________

Here the noun phrase our flight time is the subject of the clause. A clause has a
subject and a verb. there are can be other phrases, too. In this next example we use a
prepositional phrase as an adverbial.
___________________________________________________________________________
Adverbial                         Subject                Verb                 Object              Object
(prepositional phrase)    (noun phrase)     (verb phrasse)   (noun phrase)   (noun phrase)
___________________________________________________________________________
On behalf of the airline    we                        wish                  you                 a pleasant flight.
___________________________________________________________________________

For more about the difference kinds of phrases, > 4.
For subject, object, complement and adverbial, > 5.
For finite and non-finite clauses, > 239(3).

3 Sentences
A sentence can be a single clause.
     On behalf of British Island Airways, Captain Massey and his crew welcome you on
     board the Start Herald flight to Southampton.
A written sentence begins with a capital letter (On) and ends with a mark such as a
full stop.

We can also combine two or more clause in one sentence. For example, We can
use and to link the clauses.
     Our fight time will be approximately forty-five minutes, and we shall be climbing

Grammatical units > 2
The grammatical units of English are these: word, phrase, clause and sentence.

Word classes > 3
The main word classes are these: verb, noun, adjective, adverb, preposition,
determiner, pronoun and conjunction.

Phrases > 4
There are these kinds of phrase: verb phrase, noun phrase, adjective prase,
adverb phrase and prepositional phrase.

Sentence elements > 5
The sentence elements are these: subject, verb, object, complement and adverbial.

English compared with other languages >6
English words do not have a lot of ending for number and gender.
Word order is very important in English.
The verb phrase can have a complex structure.
There are many idioms with prepositions.