Interrogative Adjectives

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What Are Interrogative Adjectives? (with Examples)

An interrogative adjective is a word that modifies a noun by asking a question. Interrogative adjectives are also known as interrogative determiners. The interrogative adjectives are "what," "which," and "whose."

Interrogative adjectives modify nouns and are used in interrogative sentences (i.e., questions).

Easy Examples of Interrogative Adjectives

Here are some easy examples of interrogative adjectives (shaded):

• What car will they give us?
• Which car will they give us?
• Whose car will they give us?

Real-Life Examples of Interrogative Adjectives

Here are some examples of interrogative adjectives in real questions:

• What food have you never eaten but would like to try?
• Which apocalyptic dystopia do you think is most likely?
• Whose superpowers would you most like to have?

The Difference between "What" and "Which"

The difference between the interrogative adjectives "what" and "which" is subtle.

Use "what" when the options are unknown.

• What car will they give us?
(In this example, the speaker does not know the choice of cars available. "What" is sometimes referred to as a general determiner.)
• What dessert would you like?
(The options are unknown.)

Use "which" when the options are known.

• Which car will they give us?
(In this example, the speaker does know the choice of cars available. "Which" is sometimes referred to as a specific determiner.)
• There is a choice of three desserts on the menu. Which dessert would you like?
(The options are known.)

Interrogative Adjectives vs Interrogative Pronouns

Interrogative adjectives modify nouns or pronouns. Look at these three questions:

• Which is the greater?
• What are you buying?
• Whose shall I borrow?
(In these examples, the bold texts are not interrogative adjectives. They are interrogative pronouns. They stand alone. They do not modify nouns or pronouns.)

Compare the examples above with these similar examples:

• Which risk is the greater?
• What drinks are you buying?
• Whose jacket shall I borrow?
(These all feature interrogative adjectives.)

Interrogative Adjectives vs Interrogative Adverbs

The interrogative adverbs are "why," "where," "when," and "how." They are also used to ask questions, but the answer to these questions will be an adverb. The answer to an interrogative adjective is always a noun.

• What food would you like? (Cake)
(The answer to a question with an interrogative adjective is always something functioning as a noun, e.g., a noun, a pronoun, or a noun phrase.)
• When do you have to leave? (At four o'clock)
(The answer to a question with an interrogative adverb is always something functioning as an adverb, e.g., an adverb, an adverbial phrase, or an adverbial clause. In this example, it's an adverbial phrase of time.)

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Read more about interrogative adverbs.

Interrogative Adjectives in Indirect Questions

An interrogative adjective can also head an indirect question. An indirect question is a question embedded in a statement or another question.

• She told us which apocalyptic dystopia was most likely.
(This is an indirect question embedded in a statement.)
• Did he ask whose superpowers you would most like to have?
(This is an indirect question embedded in a question.)

Read more about indirect questions.

Why Interrogative Adjectives Are Important

Forming questions is an essential skill in any language. There is more about forming questions on the pages covering direct questions and interrogative sentences.

For native English speakers, interrogative adjectives cause few writing mistakes. By far the most common error related to interrogative adjectives is confusing "whose" and "who's."

"Who's" is short for "who is" or "who has."

Writers sometimes confuse "whose" with the contraction "who's." This is a grammatical howler.

• Who's pie is this?
• Whose pie is this?

Here's the rule:

The Rule

"Who's" is short for "who is" or "who has." This is a 100% rule.

If you can't expand your "who's" to "who is" or "who has," then it's wrong, so use "whose."

Read more about "who's" and "whose."

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