A survey of English grammar
Quirk quickly presents an outlook on grammatical units, mentioning that relation between
one unit and another unit of which it is a part is its CONSTITUENCY. Then he goes on to prove
this through the presentation of tree diagrams (see Yule, much clearer and much more to the
point). Constituents are the smaller parts into which a unit can be divided from clause to
phrase, phrase to words, words to morphemes.
The evenings have turned very cold just recently
[The evenings] [have turned] [very cold] [just recently]
[The] [evenings] [have] [turned] [very] [cold] [just] [recently]
In this tree diagram we can distinguish all the constituents of the clause. Also, we can
see the immediate constituents in each unit which are the parts into which another unit is
immediately divisible:
[have turned] VP
immediate constituent of the whole clause
auxiliary [have] + main verb [ turned] immediate constituents of the verb phrase
Each unit of a clause can be formed by an unitary constituent or a multiple
