Grammar | Interrogative adjectives

Interrogative adjectives:

Interrogative Adjective what or which, it is like an interrogative Pronoun, except that it modifies a Noun Phrase or Noun rather than standing on its own itself {see also DEMONSTRATIVE ADJECTIVES and POSSESSIVE ADJECTIVES}.

- Which programs should be watered once a week?

Interrogative adjectives

As the other Adjectives, which can be used to modify a Noun Phrase or a Noun. In that example which modifies (programs) and the Noun Phrase (which programs) is the Subject of compound Verb (should be watered).

- What car are you driving?

In this sentence what modifies (car), and the Noun Phrase (what car) is the Direct Object of the Compound Verb (are driving).