B) Conjunction test for phrasal categories

Only constituents of the same category can be conjoined

John wrote [one book] and [ten papers]

NP NP

Mary was [very tall] and [extremely clever]

AdjP AdjP

*John wrote [a book] and [to Mary]

NP PP

We can use this property of conjunction to check, for example, whether “ a car “ and “ to go to Paris” in the example below are phrases of the same type.

*John wanted [ a car] and [ to go to Paris ]

The conjunction test can also be used to provide evidence for the “single-word” phrases, i.e. phrases consisting only of a head word without any modifiers accompanying it.

John likes [Mary] and [this blonde girl with black eyes]

NP NP

Since Mary can be conjoined with what is a complex NP, it has to be considered not just a noun but a noun phrase consisting of a head noun only.

In this way the correct analysis of Mary sleeps should not be:

S but S

N V NP VP

Mary sleeps

N V

Mary sleeps

Similarly, the correct analysis of the prepositional phrase about Bill should not be:

PP but PP

P N P NP

about Bill about

N

Bill