How many interrogative adjectives does English have?

Question

Can anybody tell me exactly how many interrogative adjectives does English have? I have been researching for many days.

Some places say that there are only three interrogative adjectives: which, what, and whose. Other places say that all question words that come before a noun are interrogative adjectives, for example "why John left the college," etc. If there are only three than why can't other question words like when, why, whom, where, etc. be interrogative?

Please provide the best answer, if possible with proof.

Answer 1

English has three interrogative adjectives: we use these adjectives to ask questions:

whose, what and which.

• Whose pen is this?

• What person killed him?

• Which pen is blue?

Note that there are some interrogative pronouns, which are not neccessarily be regarded as interrogative adjectives, though whose, what and which are also interrogative pronouns. The distinction is that, the interrogative adjective modifies noun, whereas interrogative pronoun, not. Following are the interrogative pronouns:

who, what, where, when, why, whose, which, how.

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Now taking your sentence example into consideration.

"Why John left the college,"

In this sentence, 'why' doesn't modify John; in fact, it is used in its own and therefore it's a pronoun. For the correction, you could add 'did' before John:

• "Why did John leave the college?"

Thus, in this way, question words like when, whom, where are also interrogative pronouns.